RHWL has approximately 130 employees in offices in the UK, Germany and Qatar. Company files -- mostly Adobe Photoshop and InDesign, as well as CAD format -- are often very large and can sometimes go unused for long periods before needing to be accessed quickly.
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"In the short term, we tried knocking everybody off the server and agreeing with directors to archive to DVD," Allerton said. "But this created a lot of work, as well as a lot of management overhead and disruption to project teams. Backups [using BakBone Software's NetVault:Backup] were taking all weekend and eating into weekend maintenance time."
Allerton said the firm considered expanding the EMC arrays, but the price of £500 for 146 GB of capacity was considered too steep. In addition, he was wary of adding to RHWL's Fibre Channel estate for administration reasons.
"Because of Fibre Channel, EMC is quite complex," Allerton said. "It's quite high maintenance and I'm nervous about recovering data from it."
File system virtualisation adds storage, supports future growth
Allerton's team opted to spend £50,000 on two F5 Networks ARX500 file virtualisation devices and some Hewlett-Packard (HP) SATA storage capacity. The F5 devices sit on the network and present data from the EMC and HP SANs to servers as if from a common physical pool; they also place data on different storage tiers according to pre-set policies.New data, with a last modified date of six months previous, goes to the EMC Fibre Channel drive arrays. The second storage tier comprises an HP StorageWorks 60 controller with six 1 TB SATA drives.
"We didn't just want to add more storage," Allerton said. "We wanted to reduce the cost per gigabyte and gain a solution that would be much more scalable to support our future growth."
Before settling on the F5 Networks product, Allerton's team evaluated a number of software and hardware-based file system virtualisation and archiving products.
On the software side they looked at EMC DiskXtender and Symantec Enterprise Vault. They also evaluated the Brocade File Management Engine (FME) 3710, which is an appliance.
The Brocade FME product was similar to the F5 Networks device; but at three times the cost, FME was written out of the equation. At the same time, Allerton wasn't keen on the software-based products because of doubts about the way they dealt with data.
"I was put off the software products because they worked in a similar way to email archiving with stubs pointing to the files," he said. "I was worried about how this would work out in a disaster recovery scenario. I'd rather the file was actually in a known location."
Archiving saves on backup times and costs
The key gain has been that users no longer run out of disk space, so productivity isn't affected as it was previously. Allerton also calculates that RHWL has saved £243,000 in the last year because they haven't had to archive to DVD, add extra disk capacity to the EMC SAN or buy backup tapes.The weekly full backup time has also been cut from 14 hours to 1.5 hours. Archiving data that is more than six months old onto the SATA tiers has enabled this, Allerton said.
"We've shortened the full backup window by deciding not to back up tier two because, by definition, it has already been on tier one and is unmodified since it was there and backed up," Allerton said. "We've also reduced backup size by about 2 TB and now use three LTO-2 tapes instead of seven."
