Product Reviews

It's been a long time coming, but the past year has seen iSCSI move into the network storage mainstream. Dell has now joined the party, and in this UK exclusive we bring you the first hands-on review of the company's new PowerVault MD3000i, which aims to provide good-value storage consolidation to SMBs.

The MD3000i is a 3U rack chassis with room for 15 hot-swap SAS hard disks, and rather usefully they use the same carriers as Dell's latest PowerEdge servers. Dell expects to support lower-cost SATA drives, but there's no indication of when this might be. At the rear, you have room for two controller sleds each with 512MB of battery backed-up cache, two gigabit iSCSI host ports and a SAS expansion port. The latter can be used to connect up to two 15-bay Dell MD1000 units, although these are only dumb JBODs. The review system also has both controllers, which links redundancy and failover features into the equation.

The MD3000i has LSI Logic written all over it, although this is no surprise as, along with Intel and EMC, LSI and Dell are founding members of the Storage Bridge Bay Working Group, which aims to promote new storage technologies such as iSCSI. The controllers are equipped with LSI base boards and host cards, and as soon as we loaded Dell's Java-based MDSM (Modular Disk Storage Manager) we could see this was based on LSI's Simplicity Storage Manager software.

A key selling point of iSCSI is ease of installation, and with MDSM at the helm we had no problems introducing the MD3000i to our test network. The controllers each have dedicated 10/100 ethernet management ports for out-of-band management, and MDSM runs an auto-discovery routine. The array can also be managed in-band over the iSCSI host ports. Next, you carve up the physical disks into RAID arrays and create virtual drives within each one. A wizard can grab the lot and automatically create a mirror, stripe or RAID5 array with hot-standby and multiple virtual drives, or you can go for manual control, picking the drives and the number of virtual drives and their sizes. Note that the appliance doesn't support RAID6, but you can choose from RAID0, 1, 5 and 10.

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host systems are then assigned to selected virtual drives and you can place multiple hosts in groups that share the same mappings. Alternatively, you can restrict access and allow one host only to use a logical drive. Using the automatic host access routine, MDSM was unable to find our logged-in initiators. Instead, we had to use the manual host access tool, where the logged-in initiators were spotted without any problems.

Dell offers a couple of options, which it grandly calls "premium features". First up is Volume Snapshot, which takes point-in-time copies of selected virtual drives. This feature costs around £700 to license and looks of reasonable value, but it can only support four snapshots per virtual drive and a total of 128 for the array. Next is Virtual Copy, which creates a duplicate of one virtual drive to another location within the same appliance. A licence to activate both premium features costs around £1,100, which also looks good value.

For performance testing, we configured the controllers in active/active mode, connected the host ports to our gigabit network and used three Windows Server 2003 systems loaded with Microsoft's iSCSI Software Initiator 2.05. With one server, the Iometer utility reported a raw read rate of 112MB/sec when using a virtual drive on a striped array. We then logged the second server into a different host port, assigned it another dedicated virtual drive and, with Iometer running on both systems, we saw a cumulative read throughput of 219MB/sec. With three servers in the mix all using their own dedicated virtual disks, performance rose to 273MB/sec.

Performance is a winner, but the appliance has a finite expansion potential, as only two MD1000 cabinets are supported. Replication and thin provisioning aren't on the cards, either,but Dell has these covered as, at the time of review, it announced it was in the process of acquiring EqualLogic. We looked at its PS300E appliance (web ID: 83705) a while ago and were impressed with the level of features but not its price tag. Essentially, the EqualLogic systems will give Dell an enterprise-level iSCSI solution, allowing it to cover the full business spectrum with these and the MD3000i. Dell also advised us that it expects the MD3000i to support VMware ESX Server 3.5 by December, so storage virtualisation should be on the menu by the time you read this.

For its price, the PowerVault MD3000i offers a reasonable range of features teamed with good performance and plenty of redundancy. This makes it appealing to SMBs as a simple solution for consolidating network storage that's far more cost-effective than much of the competition.