St Paul's School in Barnes – which has 1,200 students and 150 members of staff -embarked on the project early last year. It was constantly running up against disk space constraints on its 18 Dell servers, a number of which were due for a four-yearly refresh. So, while considering a server upgrade and virtualisation project the school investigated a SAN implementation to provide a central store for its data.
"You can't tell in a school which will be the growth areas for the coming year," he says. "Course content can vary a lot depending on the teacher. We were coming up against capacity and looked at the budget for replacing six to eight servers but decided we might as well look at implementing a SAN. This had the added potential benefit of providing disaster recovery capability, as we have a parallel server room on campus."
The school chose a pair of EMC CX3-10C Fibre Channel SANs with a total capacity of 6.5 terabytes. The two SANs provide a central pool of storage for four Dell PowerEdge 2950 servers that run six virtual machines using VMware ESX Server 3 software. A further two Dell PowerEdge 1950 servers run a VMware Virtual Centre covering all physical and virtual machines.
Why didn't St Paul's go for an iSSCI SAN, which is widely regarded as more suited to SME-sized users?
Until early this year EMC was Dell's sole storage partner, and EMC is deeply committed to Fibre Channel. Now the outlook for Dell customers is different following the vendor's acquisition earlier this year of EqualLogic, which specialises in iSCSI SANs.
"It was just a case of timing," says Reid. "We looked at other storage vendors but at the end of the day it was about being able to pull the entire set up together and EMC was the Dell platform of choice so we had no reason not to go with that. I would have preferred the kind of flexibility that comes with an iSCSI SAN and if we'd carried out the project this year we would have got it."
He adds, "We now know it would have been cheaper and easier to manage but at the time we weren't sure of it as a technology. If it does what it says it does the EqualLogic iSCSI SAN looks good. With the Fibre Channel SAN once you allocate LUNs that's it, whereas with iSCSI you can add more disks to grow capacity a lot more easily and cheaply."
iSCSI SANs are gaining significant traction in the market, especially for use in branch office type environments and among SMEs where cost is a factor – and this is a key reason for Dell's acquisition of EqualLogic.
Recent IDC figures based on interviews with 500 European storage professionals found that 25% of them reported having an iSCSI SAN somewhere in their organisation.
Eric Sheppard, programme manager for European storage systems with IDC, says, "There is lots of interest in iSCSI SANS. Often it is seen as iSCSI versus Fibre Channel but iSCSI is of interest to customers who would never be Fibre Channel customers."
Sheppard adds that it is reaching a point where people are interested in iSCSI and understand it. Five years ago people didn't know what it was and baulked at the idea of running storage over Ethernet, both on grounds of capacity and security. Now they are far more open to the idea, he says.
Despite misgivings over missing out on an iSCSI solution, Reid is pleased with the EMC Fibre Channel SAN, which was implemented in a £120,000 project which also included eight new Dell servers and a VMWare virtualisation installation.
"It is still massively easier in terms of management," says Reid. "It means we can be much more flexible – we can designate additional servers as we need them and disk space accordingly. Previously adding new disks would have been a major operation. It has boosted our resilience considerably as we've been able to set up a parallel data room on campus."