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Why enterprise-class traditional NAS products will remain
I’ve commented before that “Unified Storage” as a differentiator is no longer the differentiator it once was, given the fact that virtually all major storage vendors are now offering a “Unified” product. Previously, only EMC and NetApp offered a true Unified storage solution. Now, IBM has SONAS built into the V7000, HP is building IBRIX into their products, HDS released the HUS platform that leverages BlueArc NAS, and Dell also is integrating Exanet into their products.
However, it’s important to note that not all Unified storage products are the same. Just because a manufacturer can “check the box” on a spec sheet that they have NAS doesn’t mean all NAS products work the same. On a related note, now that EMC has acquired Isilon, which many perceive to be a superior product to Celerra, the rumors are always going around about when will VNX File be replaced with Isilon code on the VNX series.
I’m here to tell you that:
- EMC and NetApp are still best equipped to fulfill the needs of traditional enterprise NAS use cases compared to any other vendor.
- I don’t believe Isilon will replace VNX File (Celerra) anytime soon.
- While Isilon, SONAS, IBRIX, etc are superior for scale-out use cases, that’s not the case for traditional enterprise NAS requirements.
Why is this the case? First let me clarify, when I say traditional enterprise NAS requirements, I’m talking large enterprise, as in tens of thousands of users. For a smaller shop, these don’t apply. Here are some sample requirements:
- Support for hundreds of file systems and/or mountpoints (much different than the big-data use case people talk of today involving a single file system that scales to petabytes)
- Large enterprises have dozens if not hundreds of legacy file servers. Wouldn’t it be great to consolidate these or virtualize them behind some file gateway? Sure! Is it realistic in a huge environment with thousands of custom applications that have hard-coded UNC paths to these locations, immense user disruption and re-education, etc? Not really.
- Robust NDMP support
- Large enterprises may be using advanced features of NDMP such as volume-based backup and checkpoint/snapshot based NDMP backups. Do all scale-out NAS offering support these? I don’t know to be honest but I’d be surprised.
- Number of CIFS sessions
- Handling 20,000 users logging in each morning, authenticating against AD, downloading user/group SIDs for each account, and handling drive map creations for each user that may be part of the login script is a unique requirement in its own right. It’s very intensive, but not from the standpoint of “scale-out” processing intense. Being able to open all these CIFS user sessions, maintain them, and potentially fail them over is not what scale-out NAS was designed for.
- Multiple CIFS servers
- Same point as above under multiple file systems. It’s not necessarily so simple for an organization to consolidate tens or hundreds of file servers down to one name.
- Multi-protocol support
- Scale-out NAS was not designed for corporations that have invested a lot in making their traditional NAS boxes work with advanced multi-protocol functionality, with complex mapping setup between Windows AD and Unix NIS/LDAP to allow users to access the same data from both sides with security remaining intact.
- Snapshots
- Most scale-out NAS boxes offer snapshots, but make sure they are Shadow-Copy client integrated, as most large organizations let their users/helpdesk perform their own file restores.
- Advanced CIFS functions
- Access Based Enumeration – hides shares from users who don’t have ACL rights.
- Branch Cache – increases performance at remote offices
- Robust AD integration and multi-domain support (including legacy domains)
- Migration from legacy file servers with lots of permission/SID issues.
- If you’re migrating a large file server that dates back to the stone age (NT) to a NAS, it most likely is going to have a lot of unresolvable SIDs hidden deep in its ACL’s for one reason or another. This can be a complex migration to an EMC or NetApp box. I know from experience Celerra had multiple low-level params that could be tweaked as well as custom migration scripts all designed to handle issues that can occur when you start encountering these problem SIDs during the migration. A lot of knowledge has been gained here by EMC and NetApp over the past 10 years and built into their traditional NAS products. How are scale-out NAS products designed to handle these issues? I am hard-pressed to believe that they can handle it.
The reality is that EMC’s Celerra codebase and NetApp’s ONTAP were purpose-built NAS operating systems designed to deal with these traditional enterprise requirements. SONAS, IBRIX, BlueArc, Exanet, and Isilon were not. These scale-out products (which I evaluated many years ago at a former employer and even had the opportunity to watch SONAS be developed and productized) were designed for newer scale-out use cases, often involving High Performance Computing (HPC). In fact, HPC was the sole reason my former employer looked at all of these excluding Exanet. Many of these products use SAMBA to provide their CIFS support. Isilon was just recently switched to a more enterprise-class custom CIFS stack. SONAS definitely uses SAMBA because it was built upon clustered SAMBA. HPC has completely different requirements for NAS than traditional corporate file sharing, and so companies that built products focused on the HPC market were not concerned about meeting the needs of corporate file shares.
Now this is slowly changing, as we see more traditional enterprise features being built into the latest Isilon “Mavericks” code release, particularly around security. I’m sure the other vendors are rapidly making code modifications as well now that they’ve all picked the NAS technology that they will make their SAN’s “unified” with. But it will take time to catch up to 10 years of complex Windows permission and domain integration development that Celerra/VNX and NetApp have as advantages on their side. From a quick search, it appears Isilon does not support MS Access Based Enumeration, so to think that EMC is going to dump Celerra/VNX code and plop in Isilon code on its Unified storage arrays is silly, when there are probably thousands of customers using this functionality.
A new true Unified storage contender in the market
Most folks have heard of Unified storage by now and are well aware of the basic capabilities, namely NAS and SAN in a single box. NetApp and EMC have been the primary players in this market for some time, and to date have been the only vendors to offer a true Unified solution in the enterprise arena. In using the term “true Unified”, I’m looking at the technology and determining if it is leveraging a purpose-built storage OS to handle SAN and NAS data delivery to hosts. There are other vendors out there claiming they have Unified capabilities because it is a compelling feature for customers, but by my definition taking a SAN and throwing on a Windows Storage Server to do CIFS does not count as a true Unified solution. I’m less concerned about the semantics of whether or not there are truly two code bases in the box, one serving SAN and the other serving NAS, as long as they operate from a common storage pool and have a single-point of management.
I figured the next vendor with a true Unified solution would be Dell, as multiple signs have been pointing to them integrating some NAS technology they acquired into their existing SAN platforms (Compellent and Equalogic), but surprisingly, the announcement yesterday came from IBM. IBM took the V7000 array they released last year based on SVC technology and added Unified functionality to it by leveraging their SONAS product (Scale-out NAS). I consider this to be a pretty major announcement, as NetApp and EMC can no longer claim superiority as the only Unified storage vendors with native solutions. IBM could sell OEM’d NetApp arrays (N-Series) in the past if the situation warranted, and it will be interesting to see if this announcement is the beginning of the end for the IBM-NTAP OEM relationship.
In the case of the V7000, IBM has integrated the SONAS code into the solution and made one GUI to manage it. Because the V7000 runs SVC-based code and the NAS is handled by SONAS components, it does not appear to be a unified code-base like NetApp, but two code-bases tied together with a single GUI like the VNX. From a picture I saw on Tony Pearson’s blog, they are including two IBM servers in the stack (called “File Modules” that are akin to datamovers or Filers) that run active-active sitting in front of the V7000 controllers.
I had some exposure to SONAS when I worked at a large pharma and saw its development first-hand for a project we undertook but never bought. IBM hired the guy who created SAMBA (Andrew Tridgell) to architect an active-active clustered SAMBA architecture to run on top of IBM’s Global Parallel File System (GPFS). It was a very interesting system, and Andrew Tridgell still ranks as one of the smartest people I have ever met, but back in 2007-2008 it was just a little too new. Fast forward 3 years and I’m sure the system is much more robust and fully-baked, though I’m not 100% sold on using SAMBA for CIFS access in the enterprise.
Because SONAS/GPFS is a scale-out system, the NAS functionality in the V7000 does have an advantage over EMC and Netapp in that the same file system can be served out of the two File Modules simultaneously. However, it appears the V7000 may be limited to just two file modules from what I see, unlike a full SONAS/GPFS solution or something like Isilon.
Only time will tell if the V7000 Unified will be successful and IBM will keep development of the product a hot-priority. Some folks would point to the legacy DS boxes as an example of a technology that was good when it was first released, but then sat for years without any major updates while the technology continued to evolve. But at least for the immediate future, the V7000 is certainly worthy competition in the Unified space and an example of how competition is good for the industry overall, as it forces the big gorillas to keep on their toes and continue to find new ways to innovate.
Further reading:
Hoosier Storage Guy 