The standard may have been ratified early last year but it’s only now that we’re starting to see storage devices supporting iSCSI. Overland Storage claimed the first iSCSI storage appliance to market with its REO RA2000 (see Techworld review) and now SpectraLogic announces the Spectra 2K as the first commercially available iSCSI tape library. With both these device types now available it’s possible to create a complete iSCSI storage area network over existing Gigabit Ethernet. Separate network adapters in the server can be used to link them to the iSCSI network so keeping storage requests and backup overheads away from the main network – much the same as fibre-channel but for a lot less cash
Along with iSCSI support, the version on review also supports NDMP (network data management protocol) as an option allowing it to integrate with compliant NAS appliances. Server-less backup is also another optional feature which allows storage devices supporting the SCSI protocol X-copy commands to be backed up directly over the network to the library and bypassing the server completely.
The library is very well built and can be rack mounted or placed on a tabletop on its base or side. SpectraLogic is a big supporter of Sony’s AIT format and the 2K came equipped with a pair of AIT-3 drives installed. A rotating carousel at the back of the library looks after two removable 15-slot magazines which are mounted on either side. It’s a simple system as it merely rotates through 180 degrees to present each magazine to the loader arm. The drives are located beneath so the loader only needs to travel in one dimension to access all components.
Network installation starts by providing the Gigabit Ethernet port an IP address so it can be accessed by a browser for remote management and be logged onto as an iSCSI target. A local serial port connection to the CLI is required and this presents a simple menu system that’s easy to navigate. The browser interface is just as tidy and provides basic status readouts for the controller, library and tape drives and access to log files and trace reports for troubleshooting. New features such as support for NDMP can be activated by applying a new license key but note that the 2K can only support one protocol at a time. iSCSI settings can be accessed from both interfaces. Although you can enter details such as an iSNS name the default target names assigned to the medium changer and drives cannot be modified.
To test the library we created a simple Gigabit storage area network also comprising the REO RA2000 backup accelerator and a single Windows Server 2003 system acting as the backup server and running Computer Associates ARCserve for Windows 11. We used Microsoft’s iSCSI initiator software for plain and simple ease of use. Installation doesn’t get any easier as we entered the IP address of the library as the target portal and the medium changer and tape drives immediately became available as targets. After logging on to each one they were automatically installed on the server as local devices and drivers embedded in the OS meant we didn’t even have to install these ourselves either. Securing an 8.5GB mixture of data from the appliance to the library returned an average transfer rate of 690Mbytes per minute. Further tests showed this to be a seven per cent drop in speed over a local AIT-3 tape drive.
Nothing to be seriously concerned about but we found verification and restore speeds dipped by up to thirty per cent. As the library supports jumbo frames we tried using a direct connection to the server and configured the Intel Gigabit NIC’s MTU (maximum transfer unit) at 9KB. Rerunning the same tests saw no appreciable gains and after discussing this with SpectraLogic we were unable to find any further improvements.
As the first iSCSI tape library to market, the Spectra 2K sets the pace for ease of installation and use. It provides plenty of storage capacity and is ready for the AIT-4 format when it is released this year but restore performance is a cause for concern.
From our experience we have found iSCSI much easier to implement than Fibre Channel and it costs a lot less as it can use existing copper cabling. The Spectra 2K is certainly simple to install, and provides plenty of capacity, but performance is an issue, as testing found restore speeds unacceptably low