NAS Market Heats Up

Interest seems to be picking up in the mid-range unified storage space lately. In the past month or so, we've seen Iomega and NetGear move up market with 12-drive systems with enough intestinal fortitude to host Exchange and VMware via iSCSI. Moving up-market, Xiotech, Compellent and Nimbus have all announced higher-end NAS/block systems, and rumors have been floating around that EMC is about to merge their Clariion and Celerra lines.

Enterprise players have long been buying NetApp filers or EMC Celerras, while SOHO users could take their pick of NAS boxes from companies like NetGear, Buffalo and Iomega. Mid-market organizations have been stuck with the various flavors of Windows including Windows Storage Server or expensive bottom-of-the-line systems from NetApp and EMC. Vendors like OnStor and Reldata have tried to make inroads but haven't been terribly successful, in no small part because customers never wanted to buy block storage and NAS heads from different vendors.

Mid-market block storage vendors like Xiotech and Compellent have offered Windows storage server NAS heads for years, but they haven't been real popular with users. Last year at Compellent's C Drive conference, several users pointedly asked for a faster, more capable NAS solution. Besides limited performance, especially for NFS, the WSS/SAN array combination meant that managing the file server required both Windows and storage skills.

Xiotech went the power route, bundling Symantec's FileStore scale-out NAS solution with their own ISE self-healing array modules. FileStore, based on Symantec's Storage Foundation, uses a cluster-file system to support up to 16 NAS servers in a single cluster. The combination, complete with the now ubiquitous Nehalem processors, provides scale up to 2PB and should have plenty of go-fast for all but the most demanding applications.

Compellent's new zNAS uses NexentaStor, which is based on OpenSolaris, and most importantly, ZFS. This delivers high availability failover, essentially unlimited file system capacity and most significantly, data deduplication.When most block-storage vendors OEM a NAS head, they slap their logo on the splash screen and call the system integrated. Users soon discover that they need to provision LUNs through the block-array user interface and manage the file system through the completely unrelated NAS UI.  Expanding a file system on a badly integrated solution means flipping back and forth between the two, growing the LUN and then telling the file system to recognize the additional space. Compellent has gone the extra mile and integrated NAS management into their Storage Center user interface, solving that problem.

My one disappointment with zNAS is that Compellent is only supporting flash memory in the Storage Center array.  ZFS can use internal flash for logging as a read cache but Compellent hasn't enabled these functions, relying instead on automatic tiering and STEC SSDs in the array. Some low-cost MLC in the NAS head could be a cost-effective performance boost.

So, are these really unified storage systems?  iSCSI and FC block access bypasses the NAS head to go directly to the block array, so even if the file UI is integrated, the networking isn't. NetApp, Nimbus and similar vendors use a single-storage system by building block LUNs as files in the file system.

My friend Stephen Foskett then asks, in a great blog post: "Why don't storage guys take NAS seriously" I'm still thinking about that, but expect I'll have an answer in a future blog post.