Cost was a significant factor in IBM winning the contract over a shortlist that included EMC, HP and Hitachi Data Systems.
The SAN implementation -- which will go live in March -- builds on a server consolidation programme and aims to create centralised capacity to replace an inefficient distributed storage infrastructure that had become onerous to manage, said Fraser Harris, technical support manager at SLC.
"We had had our existing storage system – HP EVA 5000s in 13 cabinets – for 10 years. We couldn't manage them efficiently with HP Storage Essentials -- they were islands of storage. We needed a lot of headroom and because they weren't consolidated we had lots of wasted space," he said.
After choosing IBM hardware from a shortlist that also included EMC, Hitachi Data Systems and HP, the SLC began to implement 280 TB worth of IBM DS8300s in two datacentres at Glasgow and Hillington, plus SVC modules at each site.
Harris' team is implementing a tiered disk arrangement with tier 1 comprising 450 GB Fibre Channel (FC) drives and tier 2 consisting of 500 GB Fibre Attached Technology Adapted (FATA) drives. The higher performing disks will be for I/O-intensive operations such as databases, Web portal serving and other live systems. Tier 2 will be reserved for test and development.
At present, only FC connectivity will be used, although Harris said iSCSI may be implemented later. "We may include iSCSI in the future to cheaply pipe backup traffic across an Ethernet link to a third site," he said.
The SLC technical team also plans to use the IBM equipment's thin-provisioning capability to cope with ongoing space requirements for its Oracle databases.
"We are a big user of Oracle databases, and they need something like three times the size of the database for Flashback recovery," Harris said. "We're hoping we can use thin provisioning to cope with that kind of sudden need for capacity without provisioning it in advance."
Thin provisioning allows storage subsystem users to allocate capacity to applications in advance without actually having that capacity physically present. As capacity is required, more storage is then added to the volume without the need for further management of provisioning. Windows files can be problematic with thin-provisioning systems, as it's not always possible to reclaim the space they take up when files are deleted. Capacity can therefore be wasted, which has conditioned Harris' use of the feature.
"NTFS isn't suitable for thin provisioning," Harris said, "so we don't use it for Windows data. But for our other data, we're going to look at it."
The key benefits for the SLC are that the IBM infrastructure will allow it to consolidate storage and make it more manageable, as well as save power and space. The new subsystem will also offer a more manageable and flexible platform to support SLC's future growth, with SVC allowing the company to bring in any other storage product at a later date and see it as part of one pool, Harris said.
"We liked the virtualisation layer in SVC, but all the offerings were pretty similar in terms of features. It was [the] cost in terms of leasing, support and expansion that made a significant difference," he said.