Rumours of tape’s demise have been greatly exaggerated, with the new Ultrium LTO-6 format strengthening its position even further. In this exclusive review, we bring you the first look at Tandberg Data’s external SAS LTO-6 drive, and put it through its paces in the labs.
The product roadmap has held firm on its promises: LTO-6 has boosted native transfer rates to 160MB/sec (from 140MB/sec) and storage capacity to an impressive 2.5TB (from 1.5TB). An increase in hardware compression to 2.5:1 can push speed and capacity to 400MB/sec and 6.25TB, although, as we found in our tests, the majority of business data can’t be compressed to that level. At the same time, support for linear tape file system (LTFS) adds new dimensions to tape as a storage medium: it allows LTFS-formatted tapes to appear to the host OS as hard disks that support drag-and-drop copies.
Two media choices are now available: Metal Particle (MP) and the newer Barium Ferrite (BaFe) cartridges. The superior magnetic properties of BaFe allow for increased areal density in future LTO generations, but LTO-7 will still be able to read and write to LTO-6 MP and read LTO-5 MP media.
On review is Tandberg’s drive kit (part code: 3535-LTO), which includes a single server copy of Backup Exec 2012 Quick Start and one LTO-6 MP data cartridge. Tandberg also offers bare external and internal drives and a version with a Fibre Channel interface.
With such high transfer rates, we needed something special to test performance, so we installed an LSI Logic SAS PCI-e card and the drive in a Dell PowerEdge R820 quad Xeon E5-4600 server running Windows Server 2008 R2 Enterprise. For storage, we used a Synology RackStation RS10613xs+ appliance to present a 1TB iSCSI target to the server over a 10GbE connection. For backup and restore tests, we loaded CA’s ARCserve r16, which required the installation of a patch to add LTO-6 support.
We used our standard 22.4GB test folder containing a mishmash of 10,500 files, and ARCserve secured them from the IP SAN storage at an average of170MB/sec. We then tested with a 100GB sample of highly compressible data and saw backup speeds increase significantly to 228MB/sec. Restore speeds are data-dependent: our 22.4GB sample averaged 110MB/sec, whereas the 100GB compressible sample returned 164MB/sec.
Jointly developed by Tandberg and HP, the Windows LTFS utility is used to format LTO cartridges and map drive letters to them. Backup speeds weren’t overly impressive: our 22.4GB data sample copied to tape at 68MB/sec. Data restoration is faster, however: the test sample returned to the server at an average of 182MB/sec. We also found speed improved using our compressible data sample, with read and write rates stepping up to 150MB/sec and 187MB/sec.
Despite its detractors – most of whom are disk-only storage vendors – tape still has an important part to play in data-protection strategies. It’s a perfect fit for the backup demands of emerging cloud storage and Big Data applications, and with LTO-6 pushing performance ever higher, LTO is now the only format worth considering for tape backup.
If you’re seeking a combination of performance, high capacity and low storage costs, Tandberg Data’s new LTO-6 HH fits the bill perfectly.
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