Review: Tandberg DPS1100

Tape libraries are big, expensive boxes, stuffed full of tape drives and robotics - right? Wrong - at least not when they’re virtual tape libraries (VTLs), like those in the Tandberg DPS1000 Series which pretend to be automated tape systems but, actually, store backups on disk. Based on industry-standard server hardware, the end result is cheaper and a lot faster than a “real” tape library, plus it makes the whole process of data protection much easier to manage.

There’s nothing particularly special about the Tandberg hardware and it’s far from large. Indeed, the DPS1100 we were sent turned out to be little more than a 1U Supermicro server, equipped with four 750GB SATA hard disks arranged as a RAID 5 array. The VTL software and a cut-down implementation of the Fedora Core OS take up some of the storage, but you still get 2.25TB for backups, which can be shared by up to 32 servers/PCs at once, each connected to its own, dedicated, virtual tape library via iSCSI.

Additional disk modules can be attached to expand capacity, up to 51TB if needed. Plus there’s a more capable 2U model (the DPS1200 at £11,087 + VAT) to support up to 64 concurrent VTLs on larger networks. A physical tape drive or library can also be connected to move backups onto conventional tape for off-site storage although, at present, support is limited to Tandberg drives only.

Supermicro servers are used extensively by appliance vendors and, although not the quietest, provide a well made and very reliable platform. Ours was, unfortunately, delivered without any documentation but, apart from a small hiccup working out what password to use, we had no problems connecting it to our test network or accessing the simple browser based GUI used for management.

Another big plus with the DPS1000 is that it emulates a standard Tandberg T40 library. And that means it can be used with all the leading backup programs, such as Backup Exec and CA ARCserve, with no need to change your existing backup policy. There’s support too for both Windows and Linux (Red Hat Enterprise Linux) initiators, although for our tests we stuck to servers running Windows Server 2003 and took backups using the built-in Microsoft backup program.

Even though the DPS1100 emulates a conventional tape library you can’t just plug it into the network and start using it. Some preparation work is required, however this took only a few minutes using the wizard provided, which we simply we downloaded to our servers from the Tandberg appliance. The wizard then both installed the Microsoft iSCSI initiator for us and configured it to connect to the DPS1100. It also installed drivers for LTO-3 tape drives and a Tandberg auto-changer to match those being emulated.

And that was about it. When we logged back onto the DPS1100 we found it had automatically created a matching virtual tape library for each server, with one virtual drive, five 200GB virtual tapes and 96 slots per VTL. That was more than adequate for our purposes, but adding extra tape drives and tapes was very easy with support for up to eight drives and unlimited tapes per VTL. We also liked the ability to move virtual tapes between libraries to, for example, restore files to another system, plus the ability to move backups out to real tape in the native backup format used.

Once our servers were configured we were able to take backups and recover files just as though attached to a “real” library. With just one server attached we got an average transfer rate of just over 50MB/s. This dropped significantly when we started to run backups from other servers at the same time, but throughput for the appliance as a whole remained at around that level regardless. Data recovery was equally as fast, with immediate access to the backups on disk rather than having to wait for tapes to be moved about, re-wound and so on.

We found the DPS1100 very easy to use. Even more so when we found copies of the “missing” documentation on the hard disk. We would have liked some of the procedures to be more obvious - for example, it took a while to track down the setup wizard – but once we’d worked out where everything was we had no real problems.

On the downside we got nothing like the 10:1 compression of data claimed. However, that’s no different from a “real” tape library and data de-duplication is planned for a future update, as are enhancements to the web-based management interface.

More of an enterprise than small business solution, the DPS1100 isn’t cheap but scores heavily against the cost of a traditional tape library even if you need to factor in expansion modules at £5,500 + VAT each. It also compares well against rival VTL products in terms of not just price but its expansion capabilities, which are hard to match.