Sheffield Hallam University picks Compellent over EMC for storage upgrade

Providing more than 35,000 students and staff with enough fast, easy-to-access data storage capacity, hosted applications and virtual learning environments without making too much work for the IT department is difficult to achieve.

But early signs of success following a recent storage area network upgrade at Sheffield Hallam University indicate that Dave Thornley, head of networks and infrastructure, has done just that.

The existing SAN was based on 50 EMC fibre channel (FC) connected servers – itself upgraded from first-generation EMC equipment since 2001 – complemented by NexSAN SATABeast arrays, Datacore SANMelody storage virtualisation software and a Texas Memory Systems RamSan solid state storage (SSD) appliance for particularly demanding Oracle and SQL database applications.

EMC was considered for the contract alongside Hitachi Data Systems (HDS) and Compellent, but based on his previous experience of SAN migration with the company, Thornley was loath to use EMC again.

“It was galling because it was an EMC-to-EMC upgrade supported by EMC people, but it took months and we had endless downtime, failing systems and migration problems,” said Thornley.

“It was a nightmare and one of the big parts of the tender was that any vendor we took on had to be able to do a drop-dead date for getting rid of EMC by 1 August, though we were viewing the prospect of moving 20TB of data in six weeks with some trepidation.”

Thornley faced other impediments, such as a static budget, datacentre power and cooling limitations, and skyrocketing data growth (primarily unstructured data from the increased use of multimedia content in teaching materials and student submissions).

But with the existing SAN equipment reaching capacity constraints and end of life in support terms, disaster recovery taking too long, and problems with automatically moving data between different storage tiers, something had to be done.

The tender was first put out in December 2009, with the actual upgrade carried out in June and July 2010 in readiness for the beginning of the current academic year’s first term.

Most of the data has now been migrated, though one small piece of mirrored data remains on a legacy server until the university gets permission to update the operating system.

The DataCore SANMelody virtualisation software and NexSAN SATABeast arrays have been retained, but the university is replacing all the EMC equipment with two identically configured Compellent storage centre arrays providing a mix of FC and SSD storage, a virtual storage pool with data managed across multiple disks on a block-by-block basis, and asynchronous replication for business continuity and disaster recovery.

All data has been written to RAID 10 and automated tiering has moved two thirds of data on to cheaper SATA hard disks without altering access times or performance.

“We went out to cost up buying new hard disks for a data warehouse application last year, but to spec that up for a flat file database required 17 spindles to provide 1TB of space,” said Thornley.

“The way Compellent manages blocks of data on virtual disks we would only need six spindles to get the same performance with a lower budget.”

The university has also got rid of the TMS RamSan appliance which Thornley says was "unbelievably expensive" – £24,000 to buy an eight-disk unit and £6,000 a year to maintain.

 “We have gone from an 84U SAN to a 30U SAN in each datacentre which has cut down on space and power,” said Thornley, adding that the SAN now requires much less management.

“We previously spent one day a week just to keep the thing up and running but the SAN administrator went on holiday for three weeks and as far as we are aware, nobody looked at the system and all the monitors were fine.”

Backup and recovery processes seem initially quicker because more snapshots can be stored, so staff do not have to waste as much time retrieving individual files from tape backups.

Students themselves have noticed the difference in terms of faster file retrieval, application performance and availability, and Thornley estimates he has doubled the storage capacity available and recovered a lot of hard disk space – 35 per cent – using thin provisioning without increasing electricity usage or the university’s carbon footprint.

“At this stage we are still finding out what the system can do: pushing more data at it and storing lots of snapshots,” said Thornley.

“With the EMC kit, for example, snapshots were always a problem and we could only have about 15 at any one time. With Compellent they are much easier to create and we can have as many as 1,500.”

Thornley could not reveal how much Sheffield Hallam spent on the upgrade in total, but insists that cost was not the overriding element when choosing a vendor – one came in with a cheaper bid but was rejected because the system offered lower running costs and simpler management, but nothing like the same functionality.

Having invested so much in Compellent storage, Thornley is naturally paying close interest to the company’s buyout by IT giant Dell in a £594m deal completed this week.

“The way Dell is as a company might be a worry, but assuming they do the same as they did with EqualLogic, or what EMC did with VMware – run it as a separate company and give it a ton of investment money – I think that is a good thing,” he said.