Dell EqualLogic PS4000E review

For replication, snapshots of selected volumes are stored in other groups called replication partners. During setup you can choose one-way replication to another group, bi-directional replication between groups, or designate one group as a central location to which multiple groups can be replicated. If a volume is lost or damaged, you can just clone a copy of the replicated volume.

Dell's SAN HeadQuarters manages multiple appliances from a central console. You can view detailed reports on capacity, which show the total space for the group and how it's split up into volumes and snapshots. A screen of combined graphs keeps you posted on network utilisation along with the number of logged-in hosts, and a separate screen provides a rundown on I/Os and average latency. The table for disk performance didn't work, however, as most of the drives showed a zero throughput. The network option has a dial showing utilisation of the virtual network port and a group summary.

We tested it by creating a RAID10 member array with all available drives, and within this we configured two 50GB partitions with access limited to our test servers by their IP addresses. We used a Broadberry CyberServe system equipped with dual 2.8GHz X5560 Xeons plus 12GB of DDR3, a Boston rack server with dual 2.5GHz L5420 Xeons and 4GB of DDR2, with both running Server 2003 R2.

Starting with the CyberServe we logged on to the first virtual volume and ran Iometer, which reported a steady raw read throughput of 112MB/sec. We confirmed that the Boston system delivered the same speed when connected to its dedicated volume, and with both servers running Iometer simultaneously we saw a cumulative throughput of 218MB/sec.

We tested further using MPIO links. Setting these up was a cinch with Dell's host integration tools: connect two physical network ports, log on to the portal and target, and Dell does the rest. Each server reported around 220MB/sec, and with both in the mix we saw this top out at a cumulative 227MB/sec.

The PS4000E is easy to deploy and is good value, including snapshots, thin provisioning and replication in the price. Add in top performance and expansion potential, and it's one classy IP SAN appliance.

Author: Dave Mitchell