HP StorageWorks D2D Backup Solution review

It’s taken a long time for many storage vendors to see the value of iSCSI to smaller business, but HP is now leading the way with a raft of new products aimed at maximising IP SANs. In this exclusive review, we take a look at its new DBS (D2D Backup Solution), which delivers a low-cost appliance with an abundance of hard disk storage, presented over iSCSI as virtual tape drives and autoloaders.

HP is by no means the first in this market, as Tandberg Data took up the challenge over 18 months ago with its BAKStor – the first product to combine iSCSI tape and disk targets. HP’s DBS differs from the BAKStor, as it presents virtual tape drives and autoloaders but not virtual disks. As with all iSCSI backup appliances, the DBS isn’t a replacement for tape, but an intermediate backup stage that still requires data to be migrated to tape for critical offsite storage. Another function it doesn’t support is locally attached tape drives – the BAKStor can handle a local SCSI tape drive and automates the copying of data held on virtual tape to it.

The appliance is simply connected to the network, where it can be accessed by multiple systems or linked directly via a network cable to a designated backup server. Either way, the appliance is able to emulate up to four tape devices, which can be single HP LTO-2 tape drives or LTO-2 autoloaders with eight to 24 slots. Note the virtual devices can’t be shared, so the appliance supports only four hosts.

Installation is smooth, as you load the product CD-ROM and follow the wizard. After loading the HP LTO-2 Windows drivers, it displays available appliances ready for network configuration. The Microsoft iSCSI initiator is downloaded and installed for you, an eight-slot LTO-2 autoloader is created on the appliance and the initiator auto-configured to log on to it with a persistent connection. The whole process took less than three minutes, and a glance in the Windows Device Manager revealed the new devices ready and waiting.

HP’s web management interface is a tidy affair, providing easy access to the various settings. You don’t have to use the wizard and can manually create new targets from the interface as desired. For the autoloader, you can decide how many virtual slots you want presented or you can create a single virtual tape drive, but you must enter the IQN of the iSCSI initiator that is to access the virtual device. You can keep a close eye on each virtual device and associated cartridges, and edit their configurations. Storage capacity may be monitored, and any problems with drives or the software RAID5 array will be flagged up as well.

For testing, we introduced the appliance to our Gigabit network and ran the setup wizard on a couple of Supermicro dual-core Xeon Windows servers. We also created a single tape drive target, and in all instances Windows and the bundled Data Protector Express had no problems identifying the virtual devices. For comparison purposes, we ran a backup and restore of a 9GB mixture of test data to a locally attached HP LTO-2 tape drive, and saw it return 35MB/sec for both tasks. We then ran the same job using the virtual tape drive, and saw each return 33MB/sec and 40MB/sec respectively.

Running two backup jobs to the appliance simultaneously produced impressive results, with the servers reporting speeds of 28MB/sec and 22MB/sec. However, iSCSI really scores when it comes to restoring specific user data, as it’s much faster. We selected a 35MB directory known to be near the end of the tape, and the LTO-2 drive took nearly two minutes to locate the files and return them. The same job using the virtual tape took a mere two seconds. We also successfully confirmed appliance operations using CA’s ARCserve and Symantec Backup Exec 11d. Don’t try using Backup Exec 10d, though, as HP advised us this software has problems working with iSCSI virtual targets.