Category Archives: Object Storage

Hail Hydra!

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The last of the Storage Field Day 6 on November 7th took me and the other delegates to NEC. There was an obvious, yet eerie silence among everyone about this visit. NEC? Are you kidding me?

NEC isn’t exactly THE exciting storage company in the Silicon Valley, yet I was pleasantly surprised with their HydraStorprowess. It is indeed quite a beast, with published numbers of backup throughput of 4PB/hour, and scales to 100PB of capacity. Most impressive indeed, and HydraStor deserves this blogger’s honourable architectural dissection.

HydraStor is NEC’s grid-based, scale-out storage platform with an object storage backend. The technology, powered by the DynamicStor ™ software, a distributed file system laid over the HydraStor grid architecture. At the same time, it has the DataRedux™ technology that provides the global in-line deduplication as the HydraStor ingests data for data protection, replication, archiving and WORM purposes. It is a massive data consolidation platform, storing gazillion loads of data (100PB you say?) for short-term and long-term retention and recovery.

The architecture is indeed solid, and its data availability goes beyond traditional RAID-level resiliency. HydraStor employs their proprietary erasure coding, called Distributed Resilient Data™. The resiliency knob can be configured to withstand 6 concurrent disks or nodes failure, but by default configured with a resiliency level of 3.

We can quickly deduce that DynamicStor™, DataRedux™ and Distributed Resilient Data™ are the technology pillars of HydraStor. How do they work, and how do they work together?

Let’s look a bit deeper into the HydraStor architecture.

HydraStor is made up of 2 types of nodes:

  • Accelerator Nodes
  • Storage Nodes

The Accelerator Nodes (AN) are the access nodes. They interface with the HydraStor front end, which could be CIFS, NFS or OST (Open Storage Technology). The AN nodes chunks the in-coming data and performs in-line deduplication at a very high speed. It can reach speed of 300TB/hour, which is blazingly fast!

The AN nodes also runs DynamicStor™, handling the performance heavy-lifting portion of HydraStor. The chunked data from the AN nodes are then passed on to the Storage Nodes (SN), where they are further “deduped in-line” to determined if the chunks are unique or not. It is a two-step inline deduplication process. Below is a diagram showing the ANs built above the SNs in the HydraStor grid architecture.

NEC AN & SN grid architecture

 

The HydraStor grid architecture is also a very scalable architecture, allow the dynamic scale-in and scale-out of both ANs and SNs. AN nodes and SN nodes can be added or removed into the system, auto-configuring and auto-optimizing while everything stays online. This capability further strengthens the reliability and the resiliency of the HydraStor.

NEC Hydrastor dynamic topology

Moving on to DataRedux™. DataRedux™ is HydraStor’s global in-line data deduplication technology. It performs dedupe at the sub-file level, with variable length window. This is performed at the AN nodes and the SN nodes level,chunking and creating unique hash values. All unique chunks are further compressed with a modified LZ compression algorithm, shrinking the data to its optimized footprint on the disk storage. To maintain the global in-line deduplication, the hash table is available across the HydraStor cluster.

NEC Deduplication & Compression

The unique data chunk resulting from deduplication and compression are then written to disks using the configured Distributed Resilient Data™ (DRD) algorithm, at its set resiliency level.

At the junction of DRD, with erasure coding parity, the data is broken up into multiples of fragments and assigned a parity to a grouping of fragments. If the resiliency level is set to 3 (the default), the data is broken into 12 pieces, 9 data fragments + 3 parity fragments. The 3 parity fragments corresponds to the resiliency level of 3. See diagram below of the 12 fragments spread across a group of selected disks in the storage pool of the Storage Nodes.

NEC DRD erasure coding on Storage Nodes

 

If the HydraStor experiences a failure in the disks or nodes, and has resulted in the loss of a fragment or fragments, the DRD self-healing function will auto-rebuild and auto-reconfigure the recovered fragments in another set of disks, maintaining the level of 3 parities.

The resiliency level, as mentioned earlier, can be set up to 6, boosting the HydraStor survival factor of 6 disks or nodes failure in the grid. See below of how the autonomous DRD recovery works:

NEC Autonomous Data recovery

Despite lacking the razzle dazzle of most Silicon Valley storage startups and upstarts, credit be given where credit is due. NEC HydraStor is indeed a strong show stopper.

However, in a market that is as fickle as storage, deduplication solutions such as HydraStor, EMC Data Domain, and HP StoreOnce, are being superceded by Copy Data Management technology, touted by Actifio. It was rumoured that EMC restructured their entire BURA (Backup Recovery Archive) division to DPAD (Data Protection and Availability Division) to go after the burgeoning copy data management market.

It would be good if NEC can take notice and turn their HydraStor “supertanker” towards the Copy Data Management market. That would be something special to savour.

P/S: NEC. Sorry about the title. I just couldn’t resist it 😉

The Prophet has arrived

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Early last week, I had a catch up with my friend. He was excited to share with me the new company he just joined. It was ProphetStor. It was a catchy name and after our conversation, I have decided to spend a bit of my weekend afternoon finding out more about the company and its technology.

From another friend at FalconStor, I knew of this company several months ago. Ex-FalconStor executives have ventured to found ProphetStor as the next generation of storage resource orchestration engine. And it has found a very interesting tack to differentiate from the many would-bes of so-called “software-defined storage” leaders. ProphetStor made their early appearance at the OpenStack Summit in Hong Kong back in November last year, positioning several key technologies including OpenStack Cinder, SNIA CDMI (Cloud Data Management Interface) and SMI-S (Storage Management Initiative Specification) to provide federation of storage resources discovery, provisioning and automation. 

The federation of storage resources and services solution is aptly called ProphetStor Federator. The diagram I picked up from the El Reg article presents the Federator working with different OpenStack initiatives quite nicely below:  There are 3 things that attracted me to the uniqueness of ProphetStor.

1. The underlying storage resources, be it files, objects, or blocks, can be presented and exposed as Cinder-style volumes.

2. The ability to define the different performance capabilities and SLAs (IOPS, throughput and latency) from the underlying storage resources and matching them to the right application requirements.

3. The use of SNIA of SMI-S and CDMI Needless to say that the Federator software will abstract the physical and logical structures of any storage brands or storage architectures, giving it a very strong validation of the “software-defined storage (SDS)” concept.

While the SDS definition is still being moulded in the marketplace (and I know that SNIA already has a draft SDS paper out), the ProphetStor SDS concept does indeed look similar to the route taken by EMC ViPR. The use of the control plane (ProphetStor Federator) and the data plane (underlying physical and logical storage resource) is obvious.

I wrote about ViPR many moons ago in my blog and I see ProphetStor as another hat in the SDS ring. I grabbed the screenshot (below) from the ProphetStor website which I thought did beautifully explained what ProphetStor is from 10,000 feet view.

ProphetStor How it works

The Cinder-style volume is a class move. It preserves the sanctity of many enterprise applications which still need block storage volumes but now it comes with a twist. These block storage volumes now will have different capability and performance profiles, tagged with the relevant classifications and SLAs.

And this is where SNIA SMI-S discovery component is critical because SMI-S mines these storage characteristics and presents them to the ProphetStor Federator for storage resource classification. For storage vendors that do not have SMI-S support, ProphetStor can customize the relevant interfaces to the proprietary API to discover the storage characteristics.

On the north-end, SNIA CDMI works with the ProphetStor Federator’s Offer & Provisioning functions to bundle wrap various storage resources for the cloud and other traditional storage network architectures.

I have asked my friend for more technology deep-dive materials (he has yet to reply me) of ProphetStor to ascertain what I have just wrote. (Simon, you have to respond to me!)

This is indeed very exciting times knowing ProphetStor as one of the early leaders in the SDS space. And I like to see ProphetStor go far with this.

Now let us pray … because the prophet has arrived.

Has Object Storage become the everything store?

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I picked up a copy of latest Brad Stone’s book, “The Everything Store: Jeff Bezos and the Age of Amazon“ at the airport on my way to Beijing last Saturday. I have been reading it my whole time I have been in Beijing, reading in awe about the turbulent ups and downs of Amazon.com.

The Everything Store cover

In its own serendipitous ways, Object-based Storage Devices (OSDs) have been floating in my universe in the past few weeks. Seems like OSDs have been getting a lot of coverage lately and suddenly, while in the shower, I just had an epiphany!

Are storage vendors now positioning Object-based Storage Devices (OSDs) as Everything Store?

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HDS HNAS kicks ass

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I am dusting off the cobwebs of my blog. After almost 3 months of inactivity, (and trying to avoid the Social Guidelines Media of my present company), I have bolstered enough energy to start writing again. I am tired, and I am finishing off the previous engagements prior to joining HDS. But I am glad those are coming to an end, with the last job in Beijing next week.

So officially, I will be in HDS as of November 4, 2013 . And to get into my employer’s good books, I think I should start with something that HDS has proved many critics wrong. The notion that HDS is poor with NAS solutions has been dispelled with a recent benchmark report from SPECSfs, especially when it comes to NFS file performance. HDS has never been much of a big shouter about their HNAS, even back in the days of OEM with BlueArc. The gap period after the BlueArc acquisition was also, in my opinion, quiet unless it was the gestation period for this Kick-Ass announcement a couple of weeks ago. Here is one of the news circling in the web, from the ever trusty El-Reg.

HDS has never been big shouting like the guys, like EMC and NetApp, who have plenty of marketing dollars to spend. EMC Isilon and NetApp C-Mode have always touted their mighty SPECSfs numbers, usually with a high number of controllers or nodes behind the benchmarks. More often than not, many readers would probably focus more on the NFSops/sec figures rather than the number of heads required to generate the figures.

Unaware of this HDS announcement, I was already asking myself that question about NFSops/sec per SINGLE controller head. So, on September 26 2013, I did a table comparing some key participants of the SPECSfs2008_nfs.v3 and here is the table:

SPECSfs2008_nfs.v3-26-Sept-2013In the last columns of the 2 halves (which I have highlighted in Red), the NFSops/sec/single controller head numbers are shown. I hope that readers would view the performance numbers more objectively after reading this. Therefore, I let you make your own decisions but ultimately, they are what they are. One should not be over-mesmerized by the super million NFSops/sec until one looks under the hood. Secondly, one should also look at things more holistically such as $/NFSops/sec, $/ORT (overall response time), and $/GB/NFSops/managed and other relevant indicators of the systems sold.

But I do not want to take the thunder away from HDS’ HNAS platforms in this recent benchmark. In summary,

HDS SPECbench summaryTo reach a respectable number of 607,647 NFSops/sec with a sub-second response time is quite incredible. The ORT of 0.59 msecs should not be taken lightly because to eke just about a 0.1 msec is not easy. Therefore, reaching 0.5 millisecond is pretty awesome.

This is my first blog after 3 months. I am glad to be back and hopefully with the monkey off my back (I am referring to my outstanding engagements), I can concentrating on writing good stuff again. I know, I know … I still owe some people some entries. It’s great to be back 🙂

Washing too much software defined

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There’s been practically a firestorm when EMC announced ViPR, its own version of “software-defined storage” at EMC World last week. Whether you want to call it Virtualization Platform Re-defined or Re-imagined, competitors such as NetApp, HDS, Nexenta have taken pot-shots at EMC, and touting their own version of software-defined storage.

In the release announcement, EMC claimed the following (a cut-&-paste from the announcement):

  • The EMC ViPR Software-Defined Storage Platform uniquely provides the ability to both manage storage infrastructure (Control Plane) and the data residing within that infrastructure (Data Plane).
  • The EMC ViPR Controller leverages existing storage infrastructures for traditional workloads, but provisions new ViPR Object Data Services (with access via Amazon S3 or HDFS APIs) for next-generation workloads. ViPR Object Data Services integrate with OpenStack via Swift and can be run against enterprise or commodity storage.
  • EMC ViPR integrates tightly with VMware’s Software Defined Data Center through industry standard APIs and interoperates with Microsoft and OpenStack.

The separation of the Control Plane and the Data Plane of the ViPR allows the abstraction of 2 main layers.

Layer 1 is the abstraction of the underlying storage hardware infrastructure. Although I don’t have the full details (EMC guys please enlighten me, please!), I believe storage administrator no longer need to carve out LUNs from RAID groups or Storage Pools, striped and sliced them and further provision them into meta file systems before they are exported or shared through NAS protocols. I am , of course, quoting the underlying provisioning architecture of Celerra, which can be quite complex. Anyone who has done manual provisioning with Celerra Manager should know what I mean.

Here’s the provisioning architecture of Celerra:

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Time for Fujitsu Malaysia to twist and shout and yet …

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The worldwide storage market is going through unprecedented change as it is making baby steps out of one of the longest recessions in history. We are not exactly out of the woods yet, given the Eurozone crisis, slowing growth in China and the little sputters in the US economy.

Back in early 2012, Fujitsu has shown good signs of taking market share in the enterprise storage but what happened to that? In the last 2 quarters, the server boys in the likes of HP, IBM and Dell storage market share have either shrunk (in the case of HP and Dell) or tanked (as in IBM). I would have expected Fujitsu to continue its impressive run and continue to capture more of the enterprise market, and yet it didn’t. Why?

I was given an Eternus storage technology update by the Fujitsu Malaysia pre-sales team more than a year ago. It has made some significant gains in technology such as Advanced Copy, Remote Copy, Thin Provisioning, and Eco-Mode, but I was unimpressed. The technology features were more like a follower, since every other storage vendor in town already has those features.

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And Cloud Storage will make us even stranger

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It was a dark and stormy night ….

I was in a car with my host in the stifling traffic jams on the streets of Jakarta. We had just finished dinner and his driver was taking me back to the hotel. It was about 9pm and we were making conversation trying to figure out how we can work together. My host, a wonderful Singaporean who has been residing in Jakarta for more than a decade and a half, owns a distributorship focusing mainly on IT security solutions. He had invited me over to Jakarta to give a talk on Cloud Storage at the Indonesia CIO Network event on January 9th 2013.

I was there to represent SNIA South Asia to give a talk about CDMI (Cloud Data Management Interface), and my host also took the opportunity to introduce Nutanix, a SAN-less 2-tier, high-performance, virtualized data center platform. (Note: That’s quite a mouthful, but gotta include all the buzz-words in there). It was my host’s first foray into storage networking solutions, away from his usual security solutions spread. As the conversation went on in the car, he said “You storage guys are so strange!“.

To many of the IT folks who have been involved in OS, applications, security, and networking, to say a few, storage is like a dark art, some mumbo jumbo, voodoo-like science known to a select few. That’s great, because this perception will keep us relevant, and still have the value and a job. To me, that just fine and dandy, and I like it that way. 🙂

In preparation to the event, I have to learn up SNIA CDMI. Cloud and Storage … Cloud and Storage … Cloud and Storage. Hmmm …. Continue reading →

Is there no one to challenge EMC?

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It’s been a busy, busy month for me.

And when the IDC Worldwide Quarterly Disk Storage Systems Tracker for 3Q12 came out last week, I was reading in awe how impressive EMC was at the figures that came out. But most impressive of all is how the storage market continue to grow despite very challenging and uncertain business conditions. With the Eurozone crisis, China experiencing lower economic growth numbers and the uncertainty in the US economic sectors, it is unbelievable that the storage market grew 24.4% y-o-y. And for the first time, 7,104PB was shipped! Yes folks, more than 7 exabytes was shipped during that period!

In the Top 5 external disk storage market based on revenue, only EMC and HDS recorded respectable growth, recording 8.7% and 13.8% respectively. NetApp, my “little engine that could” seems to be running out of steam, earning only 0.9% growth. The rest of the field, IBM and HP, recorded negative growth. Here’s a look at the Top 5 and the rest of the pack:

HP -11% decline is shocking to me, and given the woes after woes that HP has been experiencing, HP has not seen the bottom yet. Let’s hope that the new slew of HP storage products and technologies announced at HP Discover 2012 will lift them up. It also looked like a total rebranding of the HP storage products as well, with a big play on the word “Store”. They have names like StoreOnce, StoreServ, StoreAll, StoreVirtual, StoreEasy and perhaps more coming.

The Open SAN market, which includes iSCSI has EMC again at Number 1, with 29.8%, followed by IBM (14%), HDS (12.2%) and HP (11.8%). When combined with NAS numbers, the NAS + Open SAN market, EMC has 33.5% while NetApp is 13.7%.

Of course, it is just not about external storage because the direct-attached storage numbers count too. With that, the server vendors of IBM, HP and Dell are still placed behind EMC. Here’s a look at that table from IDC:

There’s a highlight of Dell in the table above. Dell actually grew by 4.0% compared to decline in HP and IBM, gaining 0.1%. However, their numbers seem too tepid and led to the exit of Darren Thomas, Dell’s storage group head honco. News of Darren’s exit was on TheRegister.

I also want to note that NAS growth numbers actually outpaced Open SAN numbers including iSCSI.

This leads me to say that there is a dire need for NAS technical and technology expertise in the local storage market. As the adoption of NFSv4 under way and SMB 2.0 and 3.0 coming into the picture, I urge all storage networking professionals who are more pro-SAN to step out of their comfort zone and look into NAS as well. The world is changing and it is no longer SAN vs NAS anymore. And NFSv4.1 is blurring the lines even more with the concepts of layout.

But back to the subject to storage market, is there no one out there challenging EMC in a big way? NetApp was, some years ago, recorded double digit growth and challenging EMC neck-and-neck, but that mantle seems to be taken over by HDS. But both are long way to go to get close to EMC.

Kudos to the EMC team for damn good execution!

HUS VM is not virtual storage appliance

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I was very confused with an recent HDS announcement, and it has been at the back of my mind for several weeks now.

On the last week of September 2012, HDS announced their Hitachi Unified Storage VM, aimed at small/medium enterprises (SMEs). Nothing wrong with that, except the VM part. I am not sure if it was the Computerworld author’s mistake, but he specifically mentioned VM as “virtual machine”. Check out the link here and the screenshot below:

It got me a bit riled up thinking this was some kind of virtual storage ala VMware Virtual Storage Appliance or NetApp ONTAP-V or even the early innovation of HP Lefthand Virtual SAN Appliance. Apparently not!

I did some short investigation and found Nigel Poulton’s blog which gave a fantastic dissection about the HUS VM. The VM is not virtual machine, but Virtual Midrange!

The HUS VM architecture is deep in ASICs, given HDS long history in ASICs design and manufacturing. SiliconFS, is the NAS front end, while the iSCSI and FC part are being serviced from the same HDS microcode of the higher end HDS VSP. Here’s a look at the hardware architectural diagram from Nigel’s blog:

There are plenty of bells and whistles in the HUS VM, armed with plenty of 8Gbps FC ports, SAS 6Gbps backend, SSDs, and software such as Dynamic Provisioning (thin provisioning) and Dynamic Tiering.

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4TB disks – the end of RAID

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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?