EXCLUSIVE: Dell EqualLogic PS5000XV

We have little doubt that iSCSI will enjoy the same rise in popularity this year as it did in 2007 and Dell gets the ball rolling by acquiring IP SAN specialist EqualLogic as it looks to improve its network storage offerings. Up until now Dell's main iSCSI product has been its PowerVault MD3000i, which we looked at in IT PRO's sister title PC Pro Business.

It's highly suited to the SMB storage market but the lack of replication and thin provisioning won't get it into the enterprise. This is where the PS family of appliances comes in, as they offer these features and much, much more.

The PS5000XV on review has performance as a top priority as all sixteen hot-swap bays are populated with 146GB Seagate Cheetah 15K.5 SAS hard disks. Fault tolerance is in abundance as the appliance sports primary and secondary hot-swap controllers plus a pair of hot-plug power supplies.

The controllers support RAID5, 10, and 50 arrays and all operations are synchronised across both controllers so the loss of one won't affect general operations. Network connections are plentiful with three copper Gigabit Ethernet ports on the primary controller up for grabs. The ports on the secondary controller provide redundancy and the primary controller automatically implements adapter teaming as each port is activated.

Storage expansion is well catered for as each physical appliance is referred to as a member and multiple appliances are gathered together in groups and presented to the network as logical storage pools.

Although each appliance looks after its own RAID arrays the storage on all members is made available as a single entity. Volumes are created within this space and presented as iSCSI targets but the volume data is spread across all appliances and drives in the group. This makes it a cinch to add more appliances to a group enabling capacity to be increased on the fly.

Dell claims a swift installation and we can agree as these appliances are very easy to set up. You have two options where you can use a serial port link and run a setup command from the CLI or use the new Windows Remote Setup Wizard. You provide a member name plus an IP address and decide whether to add the appliance to an existing group or create a new one. The Windows wizard also offers options to create single RAID-10 or -50 arrays with hot-standby from all available disks.

Thin provisioning can reduce wastage as instead of trying to create volumes that are going to be big enough to cope with future requirements you create a virtual volume that occupies a significantly smaller chunk of physical space but appears much larger to the applications using it. You can activate thin provisioning during volume creation and decide how much physical space to start with.