Bristol University has implemented an active tape archive with a disk front end using dual Spectra Logic LTO-5 tape libraries with a total (uncompressed) capacity of around 2PB.
NexSan arrays act as a disk front end to the Spectra Logic tape libraries, providing access at disk speeds for hotter data and three- to five-minute access for data committed to tape.
Bristol University’s IT team – led by systems and operations manager Graeme Cappi – opted for in-house tape over cloud archiving for long term retention. It rejected tape library products from Quantum.
The university has more than 5,000 employees and has an IT environment comprising 450 physical and virtual servers, with 125TB backed-up each week using EMC NetWorker.
Previously, user data was scattered around the campus in various systems so Cappi’s team embarked on a project to build a central archive for less time-critical data to free up more costly primary storage.
In 2012, storage systems administrator Harvey Ditchfield began to evaluate archiving systems. As part of the process, Spectra Logic lent the university a T200 tape library for a proof-of-concept project with a FileTek StorHouse software layer that abstracts the file layer to allow data management on the library.
Following a successful proof of concept, Ditchfield’s team opted to implement dual Spectra Logic tape libraries at different locations on the Bristol campus; a T950 with 950 slots with LTO-5 tapes (1.5TB capacity raw, 3TB compressed) and a T680 with 450 slots, with the help of Gloucestershire-based reseller Cristie Data.
In front of each Spectra Logic tape library is a NexSan E48 disk array with 100Tb and 40TB capacity. All archived data goes to disk, when a copy is also made to each tape library. Data continues to be retained on disk according to set policies based on age and frequency of use.
FileTek StorHouse manages the location and migration of data across the two systems. “The archive is like a NAS target, with data moving seamlessly between disk and tape,” said Ditchfield.
The cloud is increasingly attractive as an option for archive data because such services are not affected by the inherent latency encountered when traversing networks to and from a provider. Despite that, the university opted to retain archiving in-house, due to uncertainties about control over data in cloud archiving, said Ditchfield.
He said: “We haven’t excluded possibility of using the cloud and the FileTek software can use the cloud as a target. At the moment we’re not sure the cloud is really ready. Our concerns are about being able to migrate data from one cloud provider to another or bringing it back in house. We didn’t want to jump in too early.”
He added: “There are economic factors too. At present we have about half a petabyte in the tape libraries but if we take on research data too that’ll expand to about 10PB or 12PB. We want to be able to keep control of our costs and to mine data because that’s where its value lies.”
Bristol University has been a long-time user of Quantum tape hardware and evaluated the supplier’s Scalar i6000 library, but decided to go for Spectra Logic for the tape archive project.
Ditchfield said: “We have had a long and healthy relationship with Quantum, but Spectra seemed to go the extra mile, including in terms of money here, as they’re looking to expand into education; they lent us the T200 for our proof-of-concept, I like the smarts in the library and we will be able to expand in a cost-efficient manner.”