Test Center: SANs tuned for virtualization pack nice surprises
Compellent, Dell, HP, Pillar Data, and roll-your-own Pillar/DataCore bring strong storage management features to XenServer, VMware, and Hyper-V environments
Each of the systems I tested has its place, and each will suit some administrators. The Promise/DataCore system is very inexpensive, while nevertheless providing high-end storage features and great integration with most virtualization platforms. The HP offers 4Gb Fibre Channel performance and good basic storage features. The Dell EqualLogic systems offer lots of bang for the buck in storage features, and they're proven strong performers. The Compellent system offers a very mature and stable platform, with very high performance and sophisticated but easy-to-use features. Pillar Data offers a unique application-aware storage system with great performance, albeit at a significantly higher price than the other systems tested.
If you have an environment where you need to be able to run a bunch of different operating systems and don't require top end performance, but want to be able to clone images from a gold set and boot the clones, the Promise/DataCore combo or the Dell EqualLogic pair are great choices. Both provide a lot of capacity with all the features you'd want for a low cost. If you're looking for high performance with low cost and don't care about replication for disaster recovery, the HP is a good fit. If you have a number of storage admins or virtualization admins that you want to be able to provision storage without a lot of training, the Pillar Data system is an excellent though pricey choice. Finally, the all-around winner is the Compellent system, with a combination of flexibility, sophisticated features, high performance, and superior ease of use.
Compellent Storage Center 4.0
Compellent has done very well in previous tests, twice winning an InfoWorld Technology of the Year Award. It's once again in contention with an excellent overall system that combines very high performance, good capacity, great ease-of-use, and an excellent feature set.
The system I received for testing included a storage controller and two shelves of drives, a tier-one high-performance set with sixteen 300GB 15,000-rpm drives, and a tier-three high-capacity set with eight 500GB SATA drives (and room for eight more), for a total usable capacity of just over 8.5TB. All three boxes included dual controllers and dual power supplies for a fully redundant, dual-path 4Gbps Fibre Channel system. The system included all software options: server instant replay (snapshots), dynamic capacity (thin provisioning), data progression (automatic migration of data to lower tiers), and synchronous and asynchronous replication. The as-tested price of $68,709 is the second highest in this test, but not exorbitant for what you get.
Creating volumes through the browser-based admin console is simple and straightforward, and the virtualization-specific task of coalescing a number of snapshots into a new volume took less than 10 seconds for a 100GB volume. Setting up replication, even to a remote system at another location, is also a snap. The automatic migration of data to lower tiers ensures that the highest-performance drives do the heavy lifting, while data that isn't used regularly is migrated to less-expensive SATA-based storage. The system offered eight 4Gbps Fibre Channel connections, enough to support multiple VMware servers without storage bottlenecks.
Compellent also includes a full PowerShell plug-in command set for both Hyper-V and VMware environments. PowerShell, the scripting tool included with Windows Server 2008, allows for easy automation of tasks from Windows systems. The plug-in command set allows an admin to script tasks such as provisioning LUNs and volumes, configuring LUN masking, formatting volumes, installing VMs through Hyper-V Manager or VMware's Virtual Center (or vCenter Server), and installing images -- pretty much all the tasks you might want to automate when provisioning storage along with a virtual environment. The system supports full interaction with PowerShell to pull information on available volumes and perform error checking. This requires some basic programming, but still allows for complete provisioning of both Hyper-V and VMware VMs, as well as their storage, through one interface.