Category Archives: Data

4TB disks – the end of RAID

By | | , , , , , , , , ,
29 Comments

Seriously? 4 freaking terabyte disk drives?

The enterprise SATA/SAS disks have just grown larger, up to 4TB now. Just a few days ago, Hitachi boasted the shipment of the first 4TB HDD, the 7,200 RPM Ultrastar™ 7K4000 Enterprise-Class Hard Drive.

And just weeks ago, Seagate touted their Heat-Assisted Magnetic Recording (HAMR) technology will bring forth the 6TB hard disk drives in the near future, and 60TB HDDs not far in the horizon. 60TB is a lot of capacity but a big, big nightmare for disks availability and data backup. My NetApp Malaysia friend joked that the RAID reconstruction of 60TB HDDs would probably finish by the time his daughter finishes college, and his daughter is still in primary school!.

But the joke reflects something very serious we are facing as the capacity of the HDDs is forever growing into something that could be unmanageable if the traditional implementation of RAID does not change to meet such monstrous capacity.

Yes, RAID has changed since 1988 as every vendor approaches RAID differently. NetApp was always about RAID-4 and later RAID-DP and I remembered the days when EMC had a RAID-S. There was even a vendor in the past who marketed RAID-7 but it was proprietary and wasn’t an industry standard. But fundamentally, RAID did not change in a revolutionary way and continued to withstand the ever ballooning capacities (and pressures) of the HDDs. RAID-6 was introduced when the first 1TB HDDs first came out, to address the risk of a possible second disk failure in a parity-based RAID like RAID-4 or RAID-5. But today, the 4TB HDDs could be the last straw that will break the camel’s back, or in this case, RAID’s back.

RAID-5 obviously is dead. Even RAID-6 might be considered insufficient now. Having a 3rd parity drive (3P) is an option and the only commercial technology that I know of which has 3 parity drives support is ZFS. But having 3P will cause additional overhead in performance and usable capacity. Will the fickle customer ever accept such inadequate factors?

Note that 3P is not RAID-7. RAID-7 is a trademark of a old company called Storage Computer Corporation and RAID-7 is not a standard definition of RAID.

One of the biggest concerns is rebuild times. If a 4TB HDD fails, the average rebuild speed could take days. The failure of a second HDD could up the rebuild times to a week or so … and there is vulnerability when the disks are being rebuilt.

There are a lot of talks about declustered RAID, and I think it is about time we learn about this RAID technology. At the same time, we should demand this technology before we even consider buying storage arrays with 4TB hard disk drives!

I have said this before. I am still trying to wrap my head around declustered RAID. So I invite the gurus on this matter to comment on this concept, but I am giving my understanding on the subject of declustered RAID.

Panasas‘ founder, Dr. Garth Gibson is one of the people who proposed RAID declustering way back in 1999. He is a true visionary.

One of the issues of traditional RAID today is that we still treat the hard disk component in a RAID domain as a whole device. Traditional RAID is designed to protect whole disks with block-level redundancy.  An array of disks is treated as a RAID group, or protection domain, that can tolerate one or more failures and still recover a failed disk by the redundancy encoded on other drives. The RAID recovery requires reading all the surviving blocks on the other disks in the RAID group to recompute blocks lost on the failed disk. In short, the recovery, in the event of a disk failure, is on the whole object and therefore, a entire 4TB HDD has to be recovered. This is not good.

The concept of RAID declustering is to break away from the whole device idea. Apply RAID at a more granular scale. IBM GPFS works with logical tracks and RAID is applied at the logical track level. Here’s an overview of how is compares to the traditional RAID:

The logical tracks are spread out algorithmically spread out across all physical HDDs and the RAID protection layer is applied at the track level, not at the HDD device level. So, when a disk actually fails, the RAID rebuild is applied at the track level. This significant improves the rebuild times of the failed device, and does not affect the performance of the entire RAID volume much. The diagram below shows the declustered RAID’s time and performance impact when compared to a traditional RAID:

While the IBM GPFS approach to declustered RAID is applied at a semi-device level, the future is leaning towards OSD. OSD or object storage device is the next generation of storage and I blogged about it some time back. Panasas is the leader when it comes to OSD and their radical approach to this is applying RAID at the object level. They call this Object RAID.

“With object RAID, data protection occurs at the file-level. The Panasas system integrates the file system and data protection to provide novel, robust data protection for the file system.  Each file is divided into chunks that are stored in different objects on different storage devices (OSD).  File data is written into those container objects using a RAID algorithm to produce redundant data specific to that file.  If any object is damaged for whatever reason, the system can recompute the lost object(s) using redundant information in other objects that store the rest of the file.“

The above was a quote from the blog of Brent Welch, Panasas’ Director of Software Architecture. As mentioned, the RAID protection of the objects in the OSD architecture in Panasas occurs at file-level, and the file or files constitute the object. Therefore, the recovery domain in Object RAID is at the file level, confining the risk and damage of data loss within the file level and not at the entire device level. Consequently, the speed of recovery is much, much faster, even for 4TB HDDs.

Reliability is the key objective here. Without reliability, there is no availability. Without availability, there is no performance factors to consider. Therefore, the system’s reliability is paramount when it comes to having the data protected. RAID has been the guardian all these years. It’s time to have a revolutionary approach to safeguard the reliability and ensure data availability.

So, how many vendors can claim they have declustered RAID?

Panasas is a big YES, and they apply their intelligence in large HPC (high performance computing) environments. Their technology is tried and tested. IBM GPFS is another. But where are the rest?

 

Server way of locked-in storage

By | | , , , , , , , , , , ,
14 Comments

It is kind of interesting when every vendor out there claims that they are as open as they can be but the very reality is, the competitive nature of the game is really forcing storage vendors to speak open, but their actions are certainly not.

Confused? I am beginning to see a trend … a trend that is forcing customers to be locked-in with a certain storage vendor. I am beginning to feel that customers are given lesser choices, especially when the brand of the server they select for their applications  will have implications on the brand of storage they will be locked in into.

And surprise, surprise, SSDs are the pawns of this new cloak-and-dagger game. How? Well, I have been observing this for quite a while now, and when HP announced their SMART portfolio for their storage, it’s time for me to say something.

In the announcement, it was reported that HP is coming out with its 8th generation ProLiant servers. As quoted:

“The eighth generation ProLiant is turbo-charging its storage with a Smart Array containing solid state drives and Smart Caching.”

“It also includes two Smart storage items: the Smart Array controllers and Smart Caching, which both feature solid state storage to solve the disk I/O bottleneck problem, as well as Smart Data Services software to use this hardware”

From the outside, analysts are claiming this is a reaction to the recent EMC VFCache product. (I blogged about it here) and HP was there to put the EMC VFcache solution as a first generation product, lacking the smarts (pun intended) of what the HP products have to offer. You can read about its performance prowess in the HP Connect blog.

Similarly, Dell announced their ExpressFlash solution that ties up its 12th generation PowerEdge servers with their flagship (what else), Dell Compellent storage.

The idea is very obvious. Put in a PCIe-based flash caching card in the server, and use a condescending caching/tiering technology that ties the server to a certain brand of storage. Only with this card, that (incidentally) works only with this brand of servers, will you, Mr. Customer, be able to take advantage of the performance power of this brand of storage. Does that sound open to you?

HP is doing it with its ProLiant servers; Dell is doing it with its ExpressFlash; EMC’s VFCache, while not advocating any brand of servers, is doing it because VFCache works only with EMC storage. We have seen Oracle doing it with Oracle ExaData. Oracle Enterprise database works best with Oracle’s own storage and the intelligence is in its SmartScan layer, a proprietary technology that works exclusively with the storage layer in the Exadata. Hitachi Japan, with its Hitachi servers (yes, Hitachi servers that we rarely see in Malaysia), already has such a technology since the last 2 years. I wouldn’t be surprised that IBM and Fujitsu already have something in store (or probably I missed the announcement).

NetApp has been slow in the game, but we hope to see them coming out with their own server-based caching products soon. More pure play storage are already singing the tune of SSDs (though not necessarily server-based).

The trend is obviously too, because the messaging is almost always about storage performance.

Yes, I totally agree that storage (any storage) has a performance bottleneck, especially when it comes to IOPS, response time and throughput. And every storage vendor is claiming SSDs, in one form or another, is the knight in shining armour, ready to rid the world of lousy storage performance. Well, SSDs are not the panacea of storage performance headaches because while they solve some performance issues, they introduce new ones somewhere else.

But it is becoming an excuse to introduce storage vendor lock-in, and how has the customers responded this new “concept”? Things are fairly new right now, but I would always advise customers to find out and ask questions.

Cloud storage for no vendor lock-in? Going to the cloud also has cloud service provider lock-in as well, but that’s another story.

 

The marriage in the cloud

By | | , , , , ,
3 Comments

Admit it! You are a terabyte junkie! I am sure many of us have one terabyte or more of your personal “stuff” at home. Heck, I even heard from a friend that he has almost 20TB of high definition movies (thank you Torrent!) at home! That’s crazy!

And what the typical Malaysian consumer would do after he or she runs out of hard disk space? In KL (our beloved capital city, Kuala Lumpur), they would throng the Low Yat IT mall or extensions of it, like Digital Mall in PJ Section 14. In other towns and cities in Malaysia, PC fairs are popular, as consumers try to get the best price possible (We Malaysian are good at squeezing the max of a deal)

It is difficult for the not-so-IT-literate consumer to differentiate which brand is the best. Buffalo, Iomega, DLink, Western Digital, etc, etc. But the tides are changing, because these vendors want to tie you down for the rest of your digital life. You see, buying a small NAS for the home now comes with a big carrot, an incentive to keep you wanting for more, and yet you can’t unbind yourself from the tether once you are hooked.

Cloud storage hasn’t taken off in a big way last year. But many cloud storage vendors know there are plenty of opportunities out there but how do they get the consumers to upload their files, photos and whatever stuff they might have, to cloud storage? Ingeniously, they work together with other smaller NAS storage players and use these vendor’s product offerings as baits. They bundle a significantly large FREE capacity or data protection offering in the Cloud Storage as the carrot, and once the consumer decides to put their files in the cloud storage, boom, they are ensnared to become a long term ATM machine to the Cloud Storage Provider.

Sneaky? No? I call this good, smart marketing. You have a market of opportunities out there, but cloud storage isn’t catching on. You have small NAS vendors that is reaching out to the market of consumer, but it’s a brutal, competitive arena and margins are razor thin. It’s a win-win situation for both sides.

And this trend is catching on. When I first read about Drobo (a high-end consumer NAS storage) partnering Carbonite (a remote backup vendor now repackaged as a Cloud storage backup provider), I thought it was a pretty darn good idea. It was a marriage that happened in the cloud. Late last year, another consumer NAS company, QNAP paired up with Symform, a cloud storage and backup vendor.

This was moving towards a market that scratches the itch. The consumers wanted reliable backup too, but consumer-grade disk drives fail ever so often. Laptops get stolen, and files could be infected by viruses. The list goes on, but the point is that the Cloud Storage Providers may have found a silver lining in getting the consumers to leap into the cloud. And the whole idea of small NAS vendor-big Cloud Backup dynamic duo, just got a big endorsement last night. Guess who has decided to dip its grubby hands into the pie?

EMC, the 800-pound gorilla of the information and storage world, through its Iomega subsidiary, wants your money! They had just married Iomega with EMC Atmos. It was quoted:

“EMC subsidiary and data protection specialist Iomega announced the integration between Iomega network storage solutions and EMC Atmos, extending Atmos cloud-based data protection and sharing to Iomega’s network storage product offerings. The new integration gives small and midsize businesses (SMBs), remote offices and distributed enterprises access to any Atmos powered cloud around the world.”

Surprised? Not really, but I guess EMC needs to breath new life into Atmos and this marriage just extended Atmos’ life support system.

SSDs rising in the flood crisis

By | | ,
Leave a comment

The Thailand flood last year spelled disaster to the storage industry. We have already seen several big boys in the likes of HP, EMC and NetApp announcing the rise of prices because of the flood.

NetApp’s announcement is here; EMC is here; and HP is here, if you want to read about it. Below is a nice and courteous EMC letter to their customers.

But the Chinese character of “crisis” (below) also spells opportunities; opportunities for Solid State Drives (SSDs) that is.

For those of us close to the ground, the market for spinning hard disk drives (HDDs) has certainly been challenging for the past few months, especially for smaller system providers like us. Without the leveraging powers of the bigger boys, we practically had to beg to buy HDDs, not to mention the fact that the price has practically doubled.

Before the Thailand flood crisis, the GB/$ of a 2TB HDD was 0.325 Malaysian ringgit per GB. That’s about 33 cents. Today, the price is about 55 cents per GB. In comparison, at least from my experience, the GB/$ of SSDs has gone down from $5.83 to $4.99.

I know some of you might pooh-pooh the price difference between a 2TB SATA/SAS and a 120GB SSD, partly because the SSD seems so expensive. But when you consider that doing the math, the SSDs is likely to be 50x faster (at worst average) and 200x faster (at best average) for applications requiring IOPS, this could mean that transactional applications are likely to be completed an average of 100x faster, with better response time, with lower latency. This will have a domino effect on other related applications, making the entire service request performing and completing faster. When we put a price to the transactional hours, for example $10/hour work, then we can see the cost savings coming from using SSDs in the storage.

Interestingly, a friend of mine asked me about the prominence of an all SSDs storage systems. I have written about all SSDs systems in the past, and also did a high overview of Pure Storage some time back. And a very interesting fact I recalled was these systems having massive amount of IOPS. Having plenty of IOPS helps because you do away with Automated Storage Tiering (AST) because you don’t have to tier your data, and you don’t have to pay for such a feature.

Yes, all-SSDs pure-play storage systems are gaining prominence and it’s time to take notice. Nimbus beat NetApp and HP 3PAR last year to win eBay with an all SSDs storage solution and other players such as Violin Memory Systems, Pure Storage, SolidFire and of course, Texas Memory Systems (aka RAMSAN). And they are attracting big names into their management portfolios and getting VC dollars of course.

The Thailand flood aftermath will probably take 6 months or more to return to its previous production capacity prior to the crisis and SSDs can take this window of opportunity in the crisis to surge ahead. And if this flood is going to be an annual thing for Thailand (God bless Thailand), HDD market is going to have a perennial problem. And SSDs is going to rise even faster.

 

Primary Dedupe where are you?

By | | , , , , , , , , , , ,
5 Comments

I am a bit surprised that primary storage deduplication has not taken off in a big way, unlike the times when the buzz of deduplication first came into being about 4 years ago.

When the first deduplication solutions first came out, it was particularly aimed at the backup data space. It is now more popularly known as secondary data deduplication, the technology has reduced the inefficiencies of backup and helped sparked the frenzy of adulation of companies like Data Domain, Exagrid, Sepaton and Quantum a few years ago. The software vendors were not left out either. Symantec, Commvault, and everyone else in town had data deduplication for backup and archiving.

It was no surprise that EMC battled NetApp and finally won the rights to acquire Data Domain for USD$2.4 billion in 2009. Today, in my opinion, the landscape of secondary data deduplication has pretty much settled and matured. Practically everyone has some sort of secondary data deduplication technology or solution in place.

But then the talk of primary data deduplication hardly cause a ripple when compared a few years ago, especially here in Malaysia. Yeah, the IT crowd is pretty fickle that way because most tend to follow the trend of the moment. Last year was Cloud Computing and now the big buzz word is Big Data.

We are here to look at technologies to solve problems, folks, and primary data deduplication technology solutions should be considered in any IT planning. And it is our job as storage networking professionals to continue to advise customers about what is relevant to their business and addressing their pain points.

I get a bit cheesed off that companies like EMC, or HDS continue to spend their marketing dollars on hyping the trends of the moment rather than using some of their funds to promote good technologies such as primary data deduplication that solve real life problems. The same goes for most IT magazines, publications and other communications mediums, rarely giving space to technologies that solves problems on the ground, and just harping on hypes, fuzz and buzz. It gets a bit too ordinary (and mundane) when they are trying too hard to be extraordinary because everyone is basically talking about the same freaking thing at the same time, over and over again. (Hmmm … I think I am speaking off topic now .. I better shut up!)

We are facing an avalanche of data. The other day, the CEO of Nexenta used the word “data tsunami” but whatever terms used do not matter. There is too much data. Secondary data deduplication solved one part of the problem and now it’s time to talk about the other part, which is data in primary storage, hence primary data deduplication.

What is out there?  Who’s doing what in term of primary data deduplication?

NetApp has their A-SIS (now NetApp Dedupe) for years and they are good in my books. They talk to customers about the benefits of deduplication on their FAS filers. (Side note: I am seeing more benefits of using data compression in primary storage but I am not going to there in this entry). EMC has primary data deduplication in their Celerra years ago but they hardly talk much about it. It’s on their VNX as well but again, nobody in EMC ever speak about their primary deduplication feature.

I have always loved Ocarina Networks ECO technology and Dell don’t give much hoot about Ocarina since the acquisition in  2010. The technology surfaced a few months ago in Dell DX6000G Storage Compression Node for its Object Storage Platform, but then again, all Dell talks about is their Fluid Data Architecture from the Compellent division. Hey Dell, you guys are so one-dimensional! Ocarina is a wonderful gem in their jewel case, and yet all their storage guys talk about are Compellent  and EqualLogic.

Moving on … I ought to knock Oracle on the head too. ZFS has great data deduplication technology that is meant for primary data and a couple of years back, Greenbytes took that and made a solution out of it. I don’t follow what Greenbytes is doing nowadays but I do hope that the big wave of primary data deduplication will rise for companies such as Greenbytes to take off in a big way. No thanks to Oracle for ignoring another gem in ZFS and wasting their resources on pre-sales (in Malaysia) and partners (in Malaysia) that hardly know much about the immense power of ZFS.

But an unexpected source coming from Microsoft could help trigger greater interest in primary data deduplication. I have just read that the next version of Windows Server OS will have primary data deduplication integrated into NTFS. The feature will be available in Windows 8 and the architectural view is shown below:

The primary data deduplication in NTFS will be a feature add-on for Windows Server users. It is implemented as a filter driver on a per volume basis, with each volume a complete, self describing unit. It is cluster aware, and fully crash consistent on all operations.

The technology is Microsoft’s own technology, built from scratch and will be working to position Hyper-V as an strong enterprise choice in its battle for the server virtualization space with VMware. Mind you, VMware already has a big, big lead and this is just something that Microsoft must do-or-die to keep Hyper-V playing catch-up. Otherwise, the gap between Microsoft and VMware in the server virtualization space will be even greater.

I don’t have the full details of this but I read that the NTFS primary deduplication chunk sizes will be between 32KB to 128KB and it will be post-processing.

With Microsoft introducing their technology soon, I hope primary data deduplication will get some deserving accolades because I think most companies are really not doing justice to the great technologies that they have in their jewel cases. And I hope Microsoft, with all its marketing savviness and adeptness, will do some justice to a technology that solves real life’s data problems.

I bid you good luck – Primary Data Deduplication! You deserved better.

Captain Dynamo Storage System

By | | , , ,
Leave a comment

My research on file systems brought me to an very interesting piece of article. It is titled “Dynamo: Amazon’s Highly Available Key-Value Store” dated 2007.

Yes, this is an internal storage systems designed and developed in Amazon to scale and support Amazon Web Services (AWS). It is a very complex piece of technology and the paper is highly technical (not for the faint of heart). And of all places, Amazon is probably the last place you think you would find such smart technology, but it’s true. AWS engineers are slowly revealing the many of their innovations (think Amazon Silk browser technology).

And it appears that many of the latest cloud-based computing and services companies such as Amazon, Google and many others have been developing new methods of storing data objects. These methods are very different from the traditional methods of storing data, and many are no longer adopting the relational database model (RDBMS) to scale their business.

The traditional 3-tier architecture often adopted by web-based (before the advent of “cloud”), is evolving. As shown in the diagram below:

the foundation tier is usually a relational database (or a distributed relational database), communicating with the back-end storage (usually a SAN).

All that is changing because the relational database model is not keeping up with the tremendous pace of the proliferation of web-based and cloud-based objects or unstructured data. As explained by Alex Iskold, a writer of ReadWriteWeb, there are scalability issues with the conventional relational database.

 

Before I get to the scalability issues mentioned in the above diagram, let me set the floor for discussion.

For theoretical schoolers of relational database, the term ACID defines and guarantees the transactional reliability of relational databases. ACID stands for Atomicity, Consistency, Isolation and Durability. According to Wikipedia, “transactions provide an “all-or-nothing” proposition, stating that each work-unit performed in a database must either complete in its entirety or have no effect whatsoever. Further, the system must isolate each transaction from other transactions, results must conform to existing constraints in the database, and transactions that complete successfully must get written to durable storage.”

ACID has been the cornerstone of relational database from the very beginning. But as the demands of greater scalability and greater distribution of data, all 4 components of ACID – Atomicity, Consistency, Isolation, Durability – can no longer hold true. Hence, the CAP Theorem.

CAP Theorem (aka Brewer’s Theorem) stands for Consistency, Availability and Partition Tolerance. In the ACM (Association of Computing Machinery) conference in 2000, Eric Brewer of University of California, Berkeley delivered the theorem. It states that it is impossible for a distributed computer system (or a database system) to simultaneously guarantee all 3 components – Consistency, Availability and Partition Tolerance.

Therefore, as the database systems become more and more distributed in cyberspace, the ACID theorem begins to break down. All 4 components of ACID cannot be guaranteed simultaneously anymore as the database systems begin to become more and more distributed.

So when we get back to the diagram, both the concepts on left and right – Master/Slave OR Multiple Peers – will put a tremendous strain on the single, non-distributed relational database.

New data models are surfacing to handling the very distributed data sets. Distributed object-based  “file systems” and NoSQL type of databases are some of the unconventional data storage “systems” that are beginning to surface as viable alternatives to the relational database method in cyberspace. And one of them is the Amazon Dynamo Storage System. (ADSS)

ADSS is a highly available, Amazon-proprietary key-value distributed data store. ADSS has both the properties of distributed hash table and a database and it is used internally to power various Cloud Services in Amazon Web Services (AWS).

 

It behaves like a relational database where it stores data objects to be retrieved. However, the data objects are not stored in a table format of a conventional relational database. Instead, the data is stored in a distributed hash table and data content or value is retrieved with a key, hence a key-value data model.

The data content is stored and retrieved through a simple put and get interface, much like how RESTful would do it. From the article in ReadWriteWeb, here’s how Dynamo works:

  • Physical nodes are thought of as identical and organized into a ring.
  • Virtual nodes are created by the system and mapped onto physical nodes, so that hardware can be swapped for maintenance and failure.
  • The partitioning algorithm is one of the most complicated pieces of the system, it specifies which nodes will store a given object.
  • The partitioning mechanism automatically scales as nodes enter and leave the system.
  • Every object is asynchronously replicated to N nodes.
  • The updates to the system occur asynchronously and may result in multiple copies of the object in the system with slightly different states.
  • The discrepancies in the system are reconciled after a period of time, ensuring eventual consistency.
  • Any node in the system can be issued a put or get request for any key

The Dynamo architecture addresses the CAP Theorem well. It is highly available, where nodes, either physical or virtual,  can be easily swapped without affected the storage services. It is also high performance, nodes (again physical or virtual) can be added to boost the performance. The high performance and highly available components addresses the “A” piece of CAP.

Its distributed nature also allows it to scale to billions and billions of data objects and hence meets the “P” requirement of CAP. The Partitioning Tolerance is definitely there.

However, as stated by CAP Theorem, you can’t have all 3 happening at the same time. Therefore, the “C” or Consistency piece of CAP has to be compromised. That is why Dynamo has been labeled an “eventually consistency” storage system.

As data is stored into ADSS, the changes of the data is propogated and will be asynchronously replicated to other nodes in the system, eventually making all the data objects and its value consistent. However, given the speed of things in cyberspace and the nature of most Cloud Computing services, the consistency piece could be difficult to accomplish and that is OK because in most of the transactions that are distributed, inconsistency is acceptable.

So that’s a bit about the Amazon Dynamo. Alas, we may never get our grubby hands on this piece of cool data storage and management technology, but knowing that Dynamo is powering AWS and its business is an eye-opener for us into the realm of a new technology evolution.

Is there IOPS for Cloud Storage? – Nasuni style

By | | , , , ,
4 Comments

I was in Singapore last week attending the Cloud Infrastructure Services course.

In the class, one of the foundation components of Cloud Computing is of course, storage. As the students and the instructor talked about Storage, one very interesting argument surfaced. It revolved around the storage, if it was offered on the cloud. A lot of people assumed that Cloud Storage would be for their databases, and their virtual machines, which of course, is true when the communication between the applications, virtual machines and databases are in the local area network of the Cloud Service Provider (CSP).

However, if the storage is offered through the cloud to applications that are sitting on-premise in the customer’s server room, then we have to think twice of how we perceive Cloud Storage. In this aspect, the Cloud Storage offered by the CSP is a Infrastructure-as-a-Service (IaaS), where the key service is Storage. We have to differentiate that this Storage functions as a data container, and usually not for I/O performance reasons.

Though this concept probably will be easily understood by storage professionals like us, this can cause a bit confusion for someone new to the concept of Cloud Computing and Cloud Storage. This confusion, unfortunately, is caused by many of us who are vendors or solution providers, or even publications and magazines. We are responsible to disseminate correct information to customers, but due to our lack of knowledge and experience in this extremely new market of Cloud Storage, we have created the FUDs (Fear, Uncertainty and Doubt) and hype.

Therefore, it is the duty of this blogger to clear the vapourware, and hopefully pass on the right information to accelerate  the adoption of Cloud Storage in the near future. At this moment, given the various factors such as network costs, high network latency and lack of key network technologies similar to LAN in Cloud Computing, Cloud Storage is, most of the time, for data storage containership and archiving only. And there are no IOPS or any performance related statistics related to Cloud Storage. If any engineer or vendor tells you that they have the fastest Cloud Storage in the industry, do me a favour. Give him/her a knock on the head for me!

Of course, as technologies evolve, this could change in the near future. For now, Cloud Storage is a container, NOT a high performance storage in the cloud. It is usually not meant for transactional data. There are many vendors in the Cloud Storage space from real CSPs to storage companies offering re-packaged storage boxes that are “cloud-ready”. A good example of a CSP offering Cloud Storage is Amazon S3 (Simple Storage Service). And storage vendors such as EMC and HDS are repackaging and rebranding their storage technologies as object storage, ready for the cloud. EMC Atmos is really a repackaged and rebranded Centera, with some slight modifications, while HDS , using their Archiving solution, has HCP (aka HCAP). There’s nothing wrong with what EMC and HDS have done, but before the overhyping of the world of Cloud Computing, these platforms were meant for immutable data archiving reasons. Just thought you should know.

One particular company that captured my imagination and addresses the storage performance portion is Nasuni. Of course, they are quite inventive with the Cloud Storage Gateway approach. Nasuni comes up with a Cloud Storage Gateway filer appliance, which can be either a physical 1U server or as a VMware or Hyper-V virtual appliance sitting on-premise at the customer’s site.

The key to this is “on-premise”, which allows access to data much faster because they are locally-cached in the Nasuni filer appliance itself. This Nasuni filer piece addresses the Cloud Storage “performance” piece but Nasuni do not claim any performance statistics with such implementation. The clever bit is that this addresses data or files that are transactional in nature, i.e. NFS or CIFS, to serve data or files “locally”. (I wonder if Nasuni filer has iSCSI as well. Hmmmm….)

In the Nasuni architecture, they “break up” their “Cloud Storage” into 2 pieces. Piece #1 sits on-premise, at the customer site, and acts as a bridge to the Piece #2, that is sitting in a Cloud Storage. From a simplified view, have a look at the diagram below:

 

 

Piece #1 is the component that handles some of the transactional traffic related to files. In a more technical diagram below, you can see that the Nasuni filer addresses the file sharing portion, using the local disks on the filer appliance as a local caching mechanism.

 

Furthermore, older file pieces are whiffed away to the any Cloud Storage using the Cloud Connector interface, hence giving the customer a sense that their storage capacity needs can be limitless if they want to (for a fee, of course). At the same time, the Nasuni filer support thin provisioning and snapshots. How cool is that!

The Cloud Storage piece (Piece #2) is used for the data container and archiving reasons. This component can be sitting and hosted at Amazon S3, Microsoft Azure, Rackspace Cloud Files, Nirvanix Storage Delivery Network and Iron Mountain Archive Services Platform.

The data communication and transfer between the Nasuni filer is secure, encrypted, deduplication and compressed, giving it the efficiency and security that most customers would be concerned about. The diagram below explains the dat communication and data transfer bit.

 

In this manner, the Nasuni filer can replace traditional NAS platforms and can potentially provide a much lower total cost of ownership (TCO) in the long run. Nasuni does not pretend to be a NAS replacement. To me, this concept is very inventive and could potentially change the way we perceive file sharing and file server, obscuring and blurring concept of NAS.

Again, I would like to reiterate that Nasuni does not attempt to say their solution is a NAS or a performance-based Cloud Storage but what they have cleverly packaged seems to be appealing to customers. Their customer base has grown 78% in Q2 of 2011. It’s just too bad they are not here in Malaysia or this part of the world (yet).

IOPS in Cloud Storage? Not yet.

 

A little yellow elephant

By | | , , , ,
Leave a comment

By now, I believe most of you in the storage networking world would have heard of Hadoop. Hadoop was created by Doug Cutting, while he and his team was working on an open source web search engine called Nutch. The easily recognized little yellow elephant, Hadoop, was Doug Cutting’s son toy, which he made as Hadoop’s mascot. Pretty cool!

And today, Hadoop has become THE platform for Big Data applications. Why?

As I have mentioned before, everything that we do or don’t do, generates data, either as a direct product or in-direct product. I am blogging right now and I am creating data. I was in Singapore the whole of this week and everywhere I go in the MRT stations, I am being watched by the video cameras they have at the station. A new friend in class said that Singapore is the second most “watched” city after London, where there are video cameras mounted everywhere, either discreetly or indiscreetly. And that’s just video data. And there’s plenty of other human activities that generate tons and tons of data.

IDC Digital Universe Report for 2011 said that we have generated 1.8ZB (zettabyte) of data this year alone. I mentioned in my previous blog that this is a gold mine and companies are scrambling to tap on massive amount of data.  Extracting valuable information to anticipate the next trend or predict that next evolution in human preference is akin to the Gold Rush in the wild, wild west in the late 19th century. Folks, Big Data is going to be this generation’s “Digital Gold Rush”.

Sieving, filtering and processing gazillions of data (more unstructured than structured) will not work in defined, well-formatted relational databases. The data model of relational databases will simply break down. And of course, there are different schools of thoughts of different data models, but the Hadoop model seems to be gaining momentum and mind share of data scientists. That is because of Hadoop’s capability to deal with massive unstructured data, processing it and producing results in a small amount of time.

One way to process the pool of massive data is parallel programming. In parallel programming, multi-threading is commonly deployed to achieve the performance and effects of programming. But implementing multi-threading in parallel programming is difficult. Developers often has to deal with LWP (lightweight processes), semaphores, shared memory, mutex (mutually exclusive) locking and so on. Hence this style of programming works with different states on shared data, often resulting in different results in different states, even when using the same programming expression.

Hadoop belongs to another school of programming known as functional programming, where the different states on shared data concept is removed. With that in mind, the dependency on different states is also removed, resulting in a much easier and simpler parallel programming implementation. Hadoop borrows ideas from the MapReduce software framework made well known by Google and the Google File System.

Before, we get to know Hadoop, we must know MapReduce. MapReduce is a framework which allows very large data sets to be processed with a very large set of computer nodes in a cluster. Typically the computational processing is executed in a distributed fashion, spread across many computer nodes and final results are consolidated from the sub-results of these distributed processing nodes.

According to Wikipedia, the 2 key functions of Map Reduce are map() and reduce(). That’s pretty obvious. The extract below was taken from the Wikipedia definition, and explains both functions very well.

“Map” step: The master node takes the input, partitions it up into smaller sub-problems, and distributes them to worker nodes. A worker node may do this again in turn, leading to a multi-level tree structure. The worker node processes the smaller problem, and passes the answer back to its master node.

“Reduce” step: The master node then collects the answers to all the sub-problems and combines them in some way to form the output – the answer to the problem it was originally trying to solve.

The diagram below probably can simplify the concept of MapReduce to the readers.

 

Hadoop is one of the open-source implementations of MapReduce. It is one of the projects of Apache Foundation, and the project has sparked a brand-new niche of data search, data management and data science. The diagram below will allow our readers to juxtapose MapReduce and Hadoop, and comparing them in the simplest fashion.

Hadoop primary development platform is Java. Hadoop’s architecture consists mainly of 2 components – Hadoop Common and a Hadoop-compatible file system, as shown in the diagram below.

Hadoop MapReduce layer above is the file/object access interface to the Hadoop-compatible file system below. HDFS is Hadoop Distributed File System is just one of a few Hadoop-compatible file systems. Other file systems include:

  • Amazon S3 File System as part of the Amazon EC2 Infrastructure-as-a-Service (IaaS) cloud platform
  • CloudStore – a similar Hadoop-like implementation using C++ and also inspired by Google File System
  • FTP file systems
  • HTTP and HTTPS read-only file systems
  • Any file systems accessible with the file:// URL nomenclature

But the main engine of Hadoop is in the MapReduce layer. The 2 core components in this layer is JobTracker and TaskTracker. Both has their own individual roles to play and collectively, they are key cogs in the Hadoop distributed data processing model.

Below are extract I picked up from Wikipedia.

JobTracker submits MapReduce jobs to client applications. The JobTracker pushes work out to available TaskTracker nodes in the cluster, striving to keep the work as close to the data as possible. With a rack-aware filesystem, the JobTracker knows which node contains the data, and which other machines are nearby. If the work cannot be hosted on the actual node where the data resides, priority is given to nodes in the same rack. This reduces network traffic on the main backbone network. If a TaskTracker fails or times out, that part of the job is rescheduled. The TaskTracker on each node spawns off a separate Java Virtual Machine process to prevent the TaskTracker itself from failing if the running job crashes the JVM. A heartbeat is sent from the TaskTracker to the JobTracker every few minutes to check its status. The Job Tracker and TaskTracker status and information is exposed by Jetty and can be viewed from a web browser. Jetty is a Java-based HTTP server, among other things

JobTracker records what it is up to in the filesystem. When a JobTracker starts up, it looks for any such data, so that it can restart work from where it left off.

Scheduling

By default Hadoop uses first-in, first-out (FIFO), and optional 5 scheduling priorities to schedule jobs from a work queue. In version 0.19 the job scheduler was refactored out of the JobTracker, and added the ability to use an alternate scheduler (such as the Fair scheduler or the Capacity scheduler).

Fair scheduler

The fair scheduler was developed by Facebook. The goal of the fair scheduler is to provide fast response times for small jobs and QoS (Quality of Service) for production jobs. The fair scheduler has three basic concepts.

  1. Jobs are grouped into Pools.
  2. Each pool is assigned a guaranteed minimum share.
  3. Excess capacity is split between jobs.

By default jobs that are uncategorized go into a default pool. Pools have to specify the minimum number of map slots, reduce slots, and a limit on the number of running jobs.

Capacity scheduler

The capacity scheduler was developed by Yahoo. The capacity scheduler supports several features which are similar to the fair scheduler.

  • Jobs are submitted into queues.
  • Queues are allocated a fraction of the total resource capacity.
  • Free resources are allocated to queues beyond their total capacity.
  • Within a queue a job with a high level of priority will have access to the queue’s resources.

I took most the extract below from Wikipedia, and I don’t claim to be a knowledgeable person on Hadoop. All the credits go to Wikipedia editors to put Hadoop in layman terms.

Hadoop has certainly won the hearts of the new digital gold rush, Big Data and is slowly becoming a force to be reckoned with among data scientists. Hadoop implementations are powering new frontiers in processing and mining the ever growing data capacity, giving solution providers a simple programming methodology and data model to gain more insights into the vast seas of data and information.

Hadoop has many fans, and slowly becoming the data platform for large companies such as Yahoo!, Facebook, IBM, Amazon, Apple, eBay and many more. Facebook even claims to have the largest Hadoop clusters in the world, growing to 30PB in July of 2011.

This little yellow elephant is going places and one to watch out for.

Storage must go on a diet

By | | , , , , , , , ,
1 Comment

Nowadays, the capacity of the hard disk drives (HDDs) are really big. 3TB is out and 4TB is in the horizon. What’s next?

For small-medium businesses in Malaysia, depending on their data requirements and applications, 3-10TB is pretty sufficient  and with room to grow as well. Therefore, a 6TB requirement can be easily satisfied with 2 x 3TB HDDs.

If I were the customer, why would I buy a storage array, with the software licenses and other stuff that will not only increase my cost of equipment acquisition and data management, it will also increase the complexity of my IT infrastructure? I could just slot HDDs into my existing server, RAID it with RAID-0 (not a good idea but to save costs, most customers would do that) and I have a 6TB volume! It’s cheaper, easier to manage with Windows or Linux, and my system administrator doesn’t have to fuss about lack of storage experience.

And RAID isn’t really keeping up with the tremendous growth of HDD’s capacity as well. In fact, RAID is at risk. RAID (especially RAID 5/6) just cannot continue provide the LUN or volume reliability and data availability because it just takes too damn long to rebuild the volume after the failure of a disk.

Back in the days where HDDs were less than 500GB, RAID-5 would still hold up but after passing the 1TB mark, RAID-6 became more prevalent. But now, that 1TB has ballooned to 3TB and RAID-6 is on shaky ground. What’s next? RAID-7? ZFS has RAID-Z3, triple parity but come on, how many vendors have that? With triple parity or stronger RAID (is there one?), the price of the storage array is going to get too costly.

Experts have been speaking about parity-declustering,  but that’s something that a few vendors have right now. Panasas, founded by one of forefathers of RAID, Garth Gibson, comes to mind. In fact, Garth Gibson and Mark Holland of Cargenie-Mellon University’s Parallel Data Lab (PDL) presented a paper about parity-declustering more than 10 years ago.

Let’s get back to our storage fatty. Yes, our storage is getting fat, obese, rotund or whatever you want to call it. And storage vendors have been pushing a concept in hope that storage administrators and customers can take advantage of it. It is called Storage Optimization or Storage Efficiency.

Here are a few ways you can consider to put your storage on a diet.

  • Compression
  • Thin Provisioning
  • Deduplication
  • Storage Tiering
  • Tapes and SSDs

To me, compression has not taken the storage world by storm. But then again, there aren’t many vendors that tout compression as a feature for storage optimization. Most of them rather prefer to push the darling of data reduction, data deduplication, as the main feature for save more space. Theoretically, data deduplication makes more sense when the data is inactive, and has high occurrence of duplicated data. That is why secondary storage such  as backup deduplication targets like Data Domain, HP StoreOnce, Quantum DXi can publish 20:1 rates and over time, that rate can get even higher.

NetApp also has been pushing their A-SIS data deduplication on primary storage. Yes, it helps with the storage savings in primary but when the need for higher data transfer rates and time to access “manipulated” data (deduped or compressed), it is likely that compression is a better choice for primary, active data.

So who has compression? NetApp ONTAP 8.0.1 has compression now and IBM with its Storewize V7000 started as a compression device. Read about IBM Storewize in my blog here. Dell has Ocarina Networks, which was recently unleashed. I am a big fan of Ocarina Networks and I wrote about the technology in my previous blog. EMC, during the Celerra days of DART has compression but I don’t hear much about it in their VNX. Compression is there, believe me, embedded all the loads of EMC marketing.

Thin Provisioning is now a must-have and standard feature of all storage vendors. What is Thin Provisioning? The diagram below shows you:

In the past, storage systems aren’t so intelligent. You ask for 10TB, you are given 10TB and that 10TB is “deducted” from the storage capacity. That leads to wastage and storage inefficiencies. Today, Thin Provisioning will give you 10TB but storage capacity is consumed as it is being used. The capacity is not pre-allocated as in the past. Thin provisioning is a great diet pill for bloated storage projects. 

Another up and coming feature is storage tiering. Storage tiering, when associated to storage optimization, should include hierarchical storage management (HSM) and tape-out as well. Storage optimization solutions should not offer only in the storage array itself. Storage tiering within the storage array is available with most vendors – IBM EasyTier, EMC FAST2, Dell Fluid Data Management and many others. But what about data being moved out of the storage array? What about reducing the capacity of the data online or near-line? Why not put them offline if there isn’t a need for it?

I term this as Active Archiving, something I learned while I was at EMC. Here’s a look at EMC’s style of Active Archiving:

Active Archiving promotes the concept of data archiving and is not unique only to EMC. Almost all storage vendors, either natively or with 3rd party vendors, can perform fairly efficient data archiving in one way or another. One of the software that I liked (and not unique!) is Quantum Stornext. Here’s a video of how Quantum Stornext helps reduce the fat of the storage.

With the single-copy sharing feature of Quantum Stornext to multiple disparate OSes, there are lesser duplicate files in storage as well.

Tapes have been getting a bad name in the past few years. It has been repositioned and repurposed as an archive medium rather than a backup medium. But tape is the greenest and most powerful storage diet pill around. And we should not be discount tapes because tapes are fighting back. Pretty soon you will be hearing about Linear Tape File System (LTFS). In a nutshell, Linear Tape File System (LTFS) allows you to use the tape almost as if it were a hard disk. You can drag and drop files from your server to the tape, see the list of saved files using a standard operating system directory (no backup software catalog needed), and use point and click to restore. How cool is that!

And Solid State Drives (SSDs) makes sense as well.

There are times that we need IOPS and using spinning drives, we have to set up many disk spindles to achieve the IOPS that we want.  For example, using the diagram below from the godfather of storage, Greg Schulz,

The set of 16 spinning HDD drives on the left can only deliver 3,520 IOPS. The problem is, we have wasted a lot of disk space, as seen in the diagram below. This design, which most customer would be accustomed to, may look cheaper but in actual fact, is NOT.

If the price of a Fibre Channel HDD is RM2,000, the total of 16 would make up RM32,000.00. That is not inclusive of additional power and cooling and rack space and also the data management costs. Assuming the SSDs costs 5 times more than the Fibre Channel HDD. SSDs are capable of delivering very high IOPS. Here I am putting a modest 5,000 IOPS per SSDs. With just 2 SSDs (as the right design suggests), the total costs is only RM20,000. It has greater performance room to grow, and also savings in data management, power and cooling.

Folks, consider SSDs as part of your storage diet plan.

All these features are available, in whole or in part, and they are part of the storage technology offerings that is out there. With all these being said, are you doing something about it? Get off your lazy bum and start managing your storage and put your storage on a diet!!!

Crisis? What crisis?

By | | , , , ,
Leave a comment

The storage train is still chugging hard and fast as IDC just released its Worldwide Disk Storage System Tracker for 3Q11. Despite the economic climate, the storage market posted a strong 8.5% revenue growth and a whopping 30.7% growth in terms of petabytes shipped. In total, 5,429PB were shipped in Q3.

So how did everyone do in this latest Tracker report?

In the Worldwide Total External Disk Storage Systems, EMC is still holding on to the #1 position, with 28.6%. IBM and NetApp came in at 12.7% and 12.1% respectively. The table below summarizes the percentage view of the top storage players, in terms of revenue.

 

From the table, everyone benefited from the strong buying of storage in the last quarter. EMC gained a strong market gain of almost 3%, while everyone else either gained or lost less than 1% market share.  But the more interesting numbers are not from the market share column but the % growth column.

HDS posted the strongest growth of 22.1%, slightly higher than EMC of 22.0%. HDS is beginning to get their story right, putting the right storage solutions in place, and has been strongly focused in their services offering as well. That’s simply great news for HDS because this is a company is not known for their marketing and advertising. The Japanese “culture” within HDS probably has taught it to be prudent but to see HDS growing faster than the big boys like IBM and HP is something their competitors should respect. I believe customers are beginning to see the true potential of HDS.

As for EMC, everyone labels them as the 800-pound gorilla but they have been very nimble and strong in the storage market for many quarters. This is due to the strong management team headed by Joe Tucci and his heir-in-waiting, Pat Gelsinger. Several of their acquisitions are doing well, with the likes of Isilon, Greenplum, Data Domain, and of course VMware. Even though VMware does not contribute the EMC revenue numbers, the very fact that EMC owns more than 80% of VMware has already given EMC a lot of credibility in the storage battlefield. They are certainly going great guns.

NetApp took a hit in the last quarter, when they missed the street revenue numbers last quarter. Their stock took a beating and there were rumours in the market that NetApp might acquire Commvault and Quantum to compete with EMC. EMC has been able to leverage the list of companies and acquired solutions very well, from data protection solutions like Networker and Avamar, deduplication solutions like Data Domain and Avamar, Documentum for content management and so on, while NetApp has been, for the longest time, prefer a more “loosely-coupled” approach with their partners for a more complete solution set.

Other interesting reports from IDC are the Open SAN/NAS market, the NAS market and the iSCSI market.

The Open SAN/NAS market combination, according to IDC goes like this:

EMC 31.3%
NetApp 14.4%

In the NAS only market, EMC and Isilon (under the one EMC umbrella) competes with NetApp and the table is like this:

EMC 46.7%
NetApp 30.7%

The iSCSI only market is led by Dell (EqualLogic and Compellent combined), followed by EMC and IBM. Here’s the summarized table:

Dell 30.3%
EMC 19.2%
IBM 14.0%

The strong growth is indeed good news as the storage market continues to weather the economic crisis storm. I have been saying this all along. The storage market in IT is still the growth engine as data keeps growing and growing, even though it was never the darling of the IT industry. Let’s hope the trend continues.