IDC EMEA External Disk Storage Systems 2Q11 trends

Europe is the worst hit region in this present economic crisis. We have seen countries such as Greece, Portugal and Ireland being some of the worst hit countries and Italy was just downgraded last week by S&P. Last week was also the release of the 2Q2011 External Disk Storage Systems figures from IDC and the poor economic sentiments are reflected in the IDC figures as well.

Overall, the factory revenue for Western Europe grew 6% compared to the year before, but declined 5% when compared to 1Q2011. As I was reading a summary of the report, 2 very interesting trends were clear.

  • The high-end market of above USD250,000 AND the lower-end market of less than USD50,000 increased while the mid-end market of between USD50,000-100,000 price range declined
  • Sentiments revealed that storage buyers are increasingly looking for platforms that are quick to deploy and easy to manage.

As older systems are refreshed, larger companies are definitely consolidating into larger, higher-end systems to support the consolidation of their businesses and operations. Fundamentals such as storage consolidation, centralized data protection, disaster recovery and server virtualization are likely to be the key initiatives by larger organization to cut operational costs and maximizing of storage economics. This has translated to the EMEA market spending more on the higher-end storage solutions from EMC, IBM, HDS and HP.

NetApp, which has been always very strong in the mid-end market, did well to increase their market share and factory revenue at IBM’s and HP’s expense because their sales were flattish. Dell, while transitioning from its partnership with EMC to its Dell Compellent boxes, was the worst hit.

The lower-end storage solution market, according to IDC figures, increased between 10-25% depending on the price ranges of USD5,000 to USD10,000 to USD15,000. This could mean a few things but the obvious call would be the economic situation of most Western European SMBs/SMEs. This could also mean that the mid-end market could be on the decline as many of the lower-end systems are good enough to do the job. One thing the economic crisis can teach us is to be very prudent with our spendings and I believe the Western European companies are taking the same path to control their costs and maximizing their investments.

The second trend was more interesting to me. The quote of “quick to deploy and easy to manage” is definitely pushing the market to react to more off-the-shelf and open components. From an HP stand point of their Converged Infrastructure, the x86 strategy for their storage solutions is making good sense, because I believe there will be lesser need for proprietary hardware from traditional storage vendors like EMC, NetApp and others (HP included). Likewise, having storage solutions such as VSA (Virtual Storage Appliance) and storage appliance software that runs on the x86 platforms such as Nexenta and Gluster could spell out the next wave in the storage networking industry. To have things easy, specialized appliances which I have spoke much of lately, hits the requirement of “quick to deploy and easy to manage” right on the dot.

The overall fundamentals of the external disk storage systems market remain strong. Below is the present standings in the EMEA market as reported by IDC.

 

RedHat to acquire Gluster

This is breaking news. RedHat is to acquire Gluster!

What is Gluster? Gluster is a clustering Linux distribution started by Z Research under the direction of Anand Babu (who is currently Gluster’s CEO) aiming to commoditize supercomputing and supercomputing clustered storage. Gluster is open source but there is a commercial version as well. It runs on commodity 64-bit x86 hardware. The Gluster File System (GlusterFS) aggregates disks and memory resources into a pool of storage thru a single global namespace and accessed through multiple file-level protocols. The scale-out architecture is where storage resources can be added as a storage node in a building block fashion to meet performance and capacity demands, rather like what HP P4000 is doing to the block-level environment for SAN.

Gluster can integrated with most 64-bit Linux distros. This is done at the Linux user space but it can also be crafted at the Linux kernel space, where it is a software appliance, easily integrated into off-the-shelf 64-bit x86-64 platforms. This means that you can build a scale-out NAS pretty easily using your own hardware.

From an architecture standpoint, GlusterFS and its integration to a storage appliance looks like this:

 

Because it works in a modular add-on fashion, this architecture is distribution and extended by replicating the same architecture across additional x86-64 platforms (which is a storage node) as shown below.

 

It’s really easy to install Gluster and build the Scale Out NAS. I have been saving a couple videos about how Gluster is installed and I must say that it’s pretty easy. In less than 30 minutes, you can install your first Gluster storage node and then add additional nodes on the fly.

Enjoy the videos.

Video #1 (Gluster Installation)

(I have difficulty uploading the videos because WordPress requires me to purchase one of their solutions)

Video #2 (Creating and adding Storage Node in Gluster)

(I have difficulty uploading the videos because WordPress requires me to purchase one of their solutions)

Note: If you are interested to see the videos, please email to me at chin-fah.heoh@storagenetworking-academy.com.

This news gets me very excited because this is the perfect endorsement of what I have been saying all along. Storage networking and data management are the foundations of CLOUD and VIRTUALIZATION. Without data being stored and managed well, everything falls apart. And as I have mentioned many times before, this is a fantastic time to become an extra-ordinary storage engineer/consultant/architect/sales (maybe not!)

 

HP P4000 – Pretty impressive

After being in the storage networking industry for so long, I have seen most of the new storage solutions out there. Most of them don’t really differ much from what already out there, and it gets a little boring. But once in a while, a little gem is unearthed and my excitement bubbles up again.

Today, I was at the HP P4000 G2 SAN workshop and the LeftHand Networks SAN/iQ storage solution which HP acquired in 2008 left me with 3 words – Interesting, Innovative and Impressive – from a technology standpoint.

I must admit that this is a little gem that got past my radar and now it’s HP’s gain. I have heard about LeftHand Networks in the past, and at the same time, I was also looking at another storage solution called Intransa. Unfortunately, Intransa went on to differentiate themselves and today, they are focused more as a storage solution for videos and CCTVs, seldom surfacing with innovative technology. LeftHand Networks was and is different and I can understand why HP bought them, because the technology that they bring with them to HP is really cool!

Now rebranded and renamed as HP P4000 G2 SAN, the storage solution no longer sits on proprietary hardware. As part of HP’s Converged Infrastructure strategy, the SAN/iQ has been fully integrated into the HP Proliant x86 platform (I heard there’s a blade version as well), making it simple to procure and probably helps simplify operational resource planning and logistics as well. At the same, there is also a P4000 VSA (Virtual Storage Appliance) as well, which HP guys have been using for demo for several years now. There is a 60-day trial available at the HP P4000 VSA Download site, for organizations to have a try-and-buy and if they do, they can turn some of their old x86 platforms into a storage appliance by just adding more hard disk drives. That’s saves money too!

So, what’s cool, you say?

2 key technologies stands out

  • Storage Clustering
  • Network RAID

As I was well informed at the workshop today, the Storage Clustering technology is not exclusive to the P4000. In fact, Dell EqualLogic employs something similar as well. But it was something that impressed me and it is different from the traditional storage SANs that we usually see.

You see, in the traditional SAN setup, the LUNs or volumes are either loosely or tightly linked to 2 active/active storage processors/controllers. And the way most of the storage vendors do, when a customer runs out of capacity or performance or both, they would have to do a forklift upgrade of the controllers. This is something that is disruptive and also does not allow CPU, memory or I/O channels upgrade to the existing controller. Today, most storage vendors do not allow you to break open the storage processor chassis and change the CPU, add more RAM or add more I/O paths to support more disk drives or increase throughput. Mind you, this is something that I have been questioning for a long time but as the storage networking industry has it, you got to upgrade the entire storage processor or controller in order to get more power and capacity.

The P4000 (as well as the Dell EqualLogic) approaches this from another angle where instead of doing a forklift upgrade of the storage processor/controller, just add another node of the same CPU and RAM profile, and have the P4000 SAN/iQ software group the new node together with the existing node(s) to form a storage cluster group. As best practice, the Storage Cluster feature should have 16 nodes or less, but in one of the war stories shared, one customer in the US actually had 32 nodes in a Storage Cluster group, for storage capacity reasons.

As more nodes are added to the Storage Cluster group, the LUNs/volumes can be extended or spanned to the other nodes as long as they are physically connected in a Gigabit network and the entire LUN or volume is been seen as ONEΒ  irregardless of which physical nodes it may be sitting. Typically you will see this sort of thing of single “Global Namespace” concept at the file system level but this is the first time I have seen it implemented at the SAN level. (Ok, I have to admit that I am a little behind times with this technology)

Here’s a little diagram I dug up from LeftHand before it was acquired by HP which I hope will enlightened the readers about this Storage Cluster feature.

 

But the best is yet to come as the HP Solution Architect (Timothy Chua) mentioned that the Network RAID feature was uniquely LeftHand’s and way cooler. And I couldn’t agree more because this lighted me up like a spark plug!

Since Storage Clustering could span LUNs/volumes across nodes, it was only natural that the RAID capability be extended across nodes as well. RAID-10, RAID-5, RAID-6 could all be spanned across all nodes, spread the data blocks and its mirrored/parity data blocks across the nodes in the network. And the nodes does not have to at a single site. With Gigabit networks, the nodes can be separated into multiple sites as well, giving the entire solution quite a comprehensive campus-wide storage high availability. And since this is Network RAID, it gives an entirely new meaning to the word Disaster Recovery because this will eliminate the need for data replication. Primary data in a Network RAID-10 in Node 1/Site 2 could be mirrored in Node 2/Site 2, which can be further mirrored to Node 3/Site 3 and Node 4/Site 4 for a 4-way mirror. This is the P4000 Multi-site SAN solution.

The diagram below shows how Network RAID is implemented with VMware ESX.

 

And since replication is no longer a requirement, VMware’s SRM (Site Recovery Manager) is also not required as well.

It is no surprise that synchronous replication in the P4000 solution is equivalent to Network RAID. Though the concept of separating the storage controllers/nodes into multiple sites for true long-distance mirroring exists, they usually don’t exist at this level. NetApp has their Fabric and Stretch MetroCluster and EMC has their VPlex, but they usually are proposed at the higher end of the spectrum. Looks to me that HP P4000 is the only one that has this concept at the entry level iSCSI SAN level. Kudos!

They have an asynchronous replication as well for longer distance networks.

I did not stay for the demo today but I am already tickled pink about the HP P4000 technology. It had a good impression on me and I can’t wait to know more of how it works internally. Looking forward to a deeper dive of the P4000 and hope to stay for the demo next time.

More specialized appliances at Oracle OpenWorld

I was reading the news from Oracle OpenWorld and a slew of news about specialized appliances are on the menu.

Oracle added Big Data Appliance and Oracle Exalytics Business Intelligence Machine to its previous numero uno, Exadata Database Machine. EMC, also announced its Green Plum Data Computing Appliance and also its VNX Unified Storage for Oracle.

As quoted

The EMC VNX Unified Storage for Oracle is a VNX system that has 
Oracle installed in a VMware vSphere virtual machine environment. 
The system is meant to unify all Oracle environments--database over 
Oracle Direct NFS, application servers over NFS, and testing and 
development over NFS--resulting in less disk space used and faster 
testing. EMC says this configuration was made because 50% of Oracle 
customers are virtualizing their systems today.

The VNX Unified Storage for Oracle includes EMC's Fully Automated 
Storage Tiering (FAST) technology, which migrates most frequently 
used data between a primary Fibre Channel drive and solid state drives 
and migrates less frequently used data to Serial ATA (SATA) drives and 
its FAST Cache. In an Oracle environment, FAST is well-suited to 
database applications that generate a large number of random 
inputs-outputs, that experience sudden bursts in user query activity, 
or a high number of user loads and where the entire working set can 
be contained in the solid state drive cache.

Based on testing carried out on an Oracle Real Application Clusters 
(RAC) 11g database that was configured to access the VNX7500 file 
storage over the Network File System (NFS), using the Oracle 
Direct NFS (dNFS) client, results showed an 100% improvement in 
transactions per minute (TPM), 170% improvement in IOPS, and 
a 79% decrease in response time, the company said.

As for GreenPlum, EMC quoted:

The company also is showing off the EMC Greenplum Data Computing 
Appliance(DCA) for Big Data Analytics configuration, which provides 
a new migration path to Greenplum for Oracle Data Warehouse. This 
system includes the Greenplum Data Computing Appliance, EMC's 
Global Data Warehouse, and EMC's IT Business Intelligence Grid 
infrastructure. The EMC Greenplum DCA consists of 8 to 16 segment 
servers running Red Hat Enterprise Linux. Each segment server 
contains 96 to 192 processor cores, with 384 GB to 768 GB of 
memory per segment server. The DCA includes 12 600-GB Serial 
Attached SCSI (SAS) 15K RPM drives for a total useable and 
compressed capacity of 73 TB to 144 TB. The DCA competes with 
Oracle's Exadata Database Machine.

In tests performed with this server/storage configuration and a 
15-TB Oracle Data Warehouse, the DCA processed a 99 million rows 
query in less than 28 seconds vs. seven minutes in a traditional 
Oracle environment and data loads decreased from six days to 29 
minutes

It is getting pretty obvious that specialized appliances are making waves at Oracle OpenWorld but what’s more interesting is the return of a combined and integrated environment of compute and storage as I have mentioned in my previous blog. And I forsee that these specialized appliances will be one of the building blocks of cloud computing together with general purposes platforms such as x86, JBODs and the glue to all these, virtualization, notably VMware.

Storage Tiering – Responsible and Prudent

Does your IT have bottomless budget? If not, storage tiering is likely to be considered as one of IT’s weapons to combat the ever growing need for storage capacity.

Storage tiering is not new and in the past, features such as HSM (Hierarchical Storage Management) and ILM (Information Lifecycle Management) addresses storage tiering in different capacities, ranging for simple aging files movement and migration, to data objects being moved within the data infrastructure of an organization with some kind of workflow and searching capabilities.

Lately, storage tiering, and especially automated storage tiering, has been gaining prominence, thanks to the 2 high profile acquisitions – HP 3PAR and Dell Compellent. According to Wikibon,

Tiered storage is a system of assigning applications to different
types of storage media based on application requirements. Factors
considered in the allocation of storage type include the level of
protection needed, performance requirements, speed of recovery,
and many other considerations.Since assigning application data to
specific media may be complex, some vendors provide software for
automatically managing the process.

For the sake of simplicity, this blog talks about automated storage tiering within the storage array itself, where different data blocks are moved within several tiers to achieve just-right storage provisioning. Why do we need to achieve this “just-right provisioning”? Rather than discussing this from an IT, technical angle, the just-right storage provisioning should be addressed from a business and operational angle, and more rightly so, costs and benefits.

Business and operations are about managing costs and increasing profits. In the past, many storage administrators employ a single storage tier architecture. Using the same type of disks, for example, 146G 10,000RPM Fibre Channel disks, there was usually 1 or 2 RAID levels for the entire data storage requirement. Usually RAID 1+0 volumes/LUNs are for the applications that require the highest performance and availability but they come with a big cost. So, the rest of the data are kept in RAID-5 volumes/LUNs. The introduction of enterprise SATA hard disk drives basically changed the rules of the ball game, giving storage administrators another option, a cheaper alternative to store their data. Obviously, storage vendors saw the great need to address this requirement, and hence created automated storage tiering as part of their offerings.

There are quite a few storage solutions that offers the storage tiering feature, and most of them are automated as well, meaning that the data blocks are moved between the different tiers of storage within the array itself automatically. 3PAR, long before they were acquired by HP, had their Dynamic Autonomic Tiering. Today, with HP, 3PAR offers 2 key strengths in their Autonomic Tiering offering.

  • Adaptive Optimization
  • Dynamic Optimization

As HP puts it,

 

Not to be outdone, Compellent (also long before its acquisition by Dell) had the Data Progression feature as part of the Automated Storage Tiering offering. In a nutshell, their solution (which is basically similar from a 10,000 feet view with most of the competitors) is shown below.

 

The idea is to put the most frequently accessed data blocks to the most expensive, fastest, storage tier and then dynamically move the lesser accessed data block to the least expensive, most economical tier.

I have had the privilege to learn more about Compellent (before Dell) technology about 2.5 years ago, thanks to my friends Chyr and Winston, the bosses at Impact Business Solutions. And what Compellent has was pretty cool stuff and I would like to share what I have picked up about Dell Compellent storage solution. But some of the information could be a little out of date.

The foundation of Dell Compellent automated storage tiering feature, called Data Progression, is their Dynamic Block Architecture (as shown below)

 

From a high level, all data blocks are bunched together into a logical data structure called a page. A page is by default 2MB but can be configured between 512KB and 4MB. The page is the granular unit required to initiate and implement the Data Progression feature in Compellent’s automated storage tiering solution. Every page comes with attached metadata about the page such as

  • When was this page created
  • When was this page last accessed
  • Which RAID level is it currently in (RAID 1+0, RAID-59, RAID-55 and so on)
  • Which Tier does it currently reside (Tier 1, 2 or 3)
  • Which kind of disk track does it live in (Fast or Standard)

Meanwhile, there are different storage Tiers and notably, Tier 1, 2 or 3 where different disk profiles reside. Typically, the SSDs or the 15K RPM disk drives will be in Tier 1, the 10K RPM disk drives will be in Tier 2 and the slowest 7200 RPM disks will be in Tier 3.Β  Each of the 3 tiers are further divided into the outer Fast disk cylinders (where the platters spin the fastest) and the Standard disk cylinders (running in the inner tracks and slower).

As data chunks or blocks are accessed, their frequency of access and their data movement statistics are gathered in real-time, giving the Compellent solution a fairly good intelligence of how the pages should be laid out on the most relevant tiers. As the pages become more stale, and less relevant, the pages of data chunks are progressively relegated to the lower tiers, while the more active, and most relevant pages relative to importance of access, is progressively promoted to the higher tiers.

Different policies can also be configured to ensure that some important pages stay where they are regardless of their frequency of access or their relevance.

There is a very nice whitepaper from Dell detailing their Data Progression technology.

Another big automated storage tiering player is HP 3PAR. I admit that I don’t know the inner details of the HP 3PAR Dynamic Tiering solution, though I had some glossy lessons from a 3PAR Systems Engineer called Nathan Boeger (thanks to my friends at PTC Singapore, the 3PAR distributor back then) about the same time I learned about Dell Compellent. I hope HP can offer to introduce more in depth of how the 3PAR technology works, now that I have gotten cosy with some of the HP Malaysia’s folks.

Similarly, the other big boys are offering the automated storage tiering solution as well. IBM has been offering Easy Tier for almost 18 months and EMC has its FAST2 for about the same time.

Funnily, the odd one out in this automated storage tiering game is NetApp. I was in a partner conference call about 1 year ago and there were questions asking NetApp about their views of automated storage tiering. At that time of the concall, NetApp did not believe in automated storage tiering, preferring to market their FlashCache PCIe (previously called the PAM card) solution. Take note that the FlashCache is a Read-Only “extension” to their NVRAM, and used to accelerate read operations of WAFL. And also take note that NetApp, at the time of writing, does not have an “engine” that performs automated storage tiering, regardless of how they spin it.

There are also host-based file tiering solutions as well.Since I am familiar with the NetApp universe, Arkivio and Enigma Data Solutions are 2 of the main partners that NetApp works with. Recently NetApp also resells StorNext from Quantum. But note that these host-based solutions are file-based, making them less granular, less dynamic and less efficient. They are usually marketed as file archiving solutions, and the host-based license are usually charged by per TB. In large enterprises, this might make sense but for the everyday Joes (with tight IT budgets), host-based file archiving solutions are expensive. And it is nowhere close to the efficiencies of automated storage tiering.

Overall, automated storage tiering, when applied, should help the IT operations and the organization’s business reduce costs. There is no longer a one-size-fit-all model and associating the right storage tier to the relevance and importance of the data at a very granular sub-LUN/sub-volume level will help any organization define a more prudent approach in managing their data actively and more importantly their cost of operations.

This is called Responsible IT. πŸ˜€

ONTAP vs ZFS

I have to get this off my chest. Oracle’s Solaris ZFS is better than NetApp’s ONTAP WAFL! There! I said it!

I have been studying both similar Copy-on-Write (COW) file systems at the data structure level for a while now and I strongly believe ZFS is a better implementation of the COW file systems (also known as “shadow-paging” file system) than WAFL. How are both similar and how are both different? The angle we are looking at is not performance but about resiliency and reliability.

(Note: btrfs or “Butter File System” is another up-and-coming COW file system under GPL license and is likely to be the default file system for the coming Fedora 16)

In Computer Science, COW file system are tree-like data structures as shown below. They are different than the traditional Berkeley Fast File System data structure as shown below:

As some of you may know, Berkeley Fast File System is the foundation of some modern day file systems such as Windows NTFS, Linux ext2/3/4, and Veritas VxFS.

COW file system is another school of thought and this type of file system is designed in a tree-like data structure.

In a COW file system or more rightly named shadow-paging file system, the original node of the data block is never modified. Instead, a copy of the node is created and that copy is modified, i.e. a shadow of the original node is created and modified. Since the node is linked to a parent node and that parent node is linked to a higher parent node and so on all the way to the top-most root node, each parent and higher-parent nodes are modified as it traverses through the tree ending at the root node.

The diagram below shows the shadow-paging process in action as modifications of the node copy and its respective parent node copies traverse to the top of the tree data structure. The diagram is from ZFS but the same process applies to WAFL as well.

 

As each data block of either the leaf node (the last node in the tree) or the parent nodes are being modified, pointers to either the original data blocks or the copied data blocks are modified accordingly relative to the original tree structure, until the last root node at the top of the shadow tree is modified. Then, the COW file system commit is considered complete. Take note that the entire process of changing pointers and modifying copies of the nodes of the data blocks is done is a single I/O.

The root at the top for ZFS is called uberblock and called fsinfo in WAFL. Because an exact shadow of the tree-like file system is created when the data blocks are modified, this also gives birth to how snapshots are created in a COW file system. It’s all about pointers, baby!

Here’s how it looks like with the original data tree and the snapshot data tree once the shadow paging modifications are complete.

 

However, there are a few key features from the data integrity and reliability point of view where ZFS is better than WAFL. Let me share that with you.

In a nutshell, ZFS is a layered architecture that looks like this

The Data Management Unit (DMU) layer is one implementation that ensures stronger data integrity. The DMU maintains a checksum on the data in each data block by storing the checksum in the parent’s blocks. Thus if something is messed up in the data block (possibly by Silent Data Corruption), the checksum in the parent’s block will be able to detect it and also repair the data corruption if there is sufficient data redundancy information in the data tree.

WAFL will not be able to detect such data corruptions because the checksum is applied at the disk block level and the parity derived during the RAID-DP write does not flag this such discrepancy. An old set of slides I found portrayed this comparison as shown below.

 

Another cool feature that addresses data resiliency is the implementation of ditto blocks. Ditto blocks stores 3 copies of the metadata and this allows the recovery of lost metadata even if 2 copies of the metadata are deleted.

Therefore, the ability of ZFS to survive data corruption, metadata deletion is stronger when compared to WAFL .This is not discredit NetApp’s WAFL. It is just that ZFS was built with stronger features to address the issues we have with storing data in modern day file systems.

There are many other features within ZFS that have improved upon NetApp’s WAFL. One such feature is the implementation of RAID-Z/Z2/Z3. RAID-Z is a superset implementation of the traditional RAID-5 but with a different twist. Instead of using fixed stripe width like RAID-4 or RAID-DP, RAID-Z/Z2 uses a dynamic variable stripe width. This addressed the parity RAID-4/5 “write hole” flaw, where incomplete or partial stripes will result in a “hole” that leads to file system fragmentation. RAID-Z/Z2 address this by filling up all blocks with variable stripe width. A parity can be calculated and assigned with any striped width, as shown below.

 

Other really cool stuff are Hybrid Storage Pool and the ability to create software-based caching using fast disk drives such as SSDs. This approach of creating ReadZilla (read caching) and LogZilla (write caching) eliminates the need for proprietary NVRAM as implemented in NetApp’s WAFL.

The only problem is, despite the super cool features of ZFS, most Oracle (not Sun) sales does not have much clue how to sell ZFS storage. NetApp, with its well trained and tuned, sales force is beating Oracle to pulp.