Tape vs Disc - the new battle

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As organisations of all sorts, in the public and private sectors, struggle with growing amounts of data, much of which must be backed-up safely by law, the issue of what constitutes a secure but also economic back up strategy remains at the forefront of many IT professionals' minds.

Here we talk to two senior IT professionals in two different sectors about the role of tape and disk in the enterprise.

Richard Bates, network manager for Warwick District Council

Warwick District Council employs 20 people in its IT department, serving over 600 users, 400 of them on its main site and the rest in small, local offices.

"We've always used HP for both servers and storage," says Bates. "We made a move to networked storage five years ago with the StorageWorks MSA1000. We decided to centralise our back up onto tape at the same time. We realised that that was the way to go and moved onto an EVA 3000 array with Fibre Channel connectivity."

At the time, the authority's data storage needs were expanding hugely, says Bates, making this move not simply desirable but essential.

"We were no longer allowing users to save stuff onto their desktop, so all data was going onto our central server - for security reasons mainly," he says. "The number of photos and large documents we were storing was just growing and growing - especially once we got a document management project started which meant we were storing an image of all the post we received. The databases in use with the various departments just seemed to keep growing too."

Bates realised it was time to review his back-up strategy again when the back up window stretched all night: "It was often still going in the morning when everyone turned up for work, slowing the network down no end," he says.

Another hardware upgrade followed: "We got an EVA 5000, and kept the EVA 3000 to replicate everything on to and give us a degree of disaster recovery capability," says Bates. "We then moved the MSA1000 to a staging job in the back up process, shifting data from disk to tape."

He says the core of his back-up process is now replication between the two SAN arrays, but still backed by tape: "It's just so reliable, it's cheap, and it means I can easily take back-up data and store it off site," he says. "I keep hearing about people who've moved the back up function entirely onto disk, but I can't see any reason to. Getting rid of tape is just not an option for me at the moment. In the future? I really can't say. I'm sure we'll be using tape for a few years yet. You just feel more secure with tape. Disks do crash, don't they?"

He says future plans include moving one of the SANs to a remote office and connecting it over a wide area link: "It's obviously something that would be technically feasible right now, but it would be expensive," he says. "Although I can't justify this move at present, technology might well move on and make it possible in the future."

With no remote site in operation at present, Bates says he always has to look at what might go wrong with data and plan accordingly: "At the moment, we could lose a floor to, say, a flood, and be OK, but losing the whole building would be a true disaster."

Another possible move for the future is to virtualise all servers, he says, perhaps adopting blade technology: "Blades look good to me, or at least the HP ones I've seen. We're looking into it at the moment."

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