Product Reviews

When it comes to choosing enterprise-level network storage, the majority of vendors want to lock you into their choice of array cabinet and hard disk. We've seen this with NetApp's FAS3020 and HP's StorageWorks Modular Smart Array 1500 cs, where the controller and disk array are integral parts of a complete package.

Reldata offers an interesting alternative, as it only provides the head unit. This allows you to choose any storage hardware you want, since it supports both SCSI and Fibre Channel (FC) disk arrays. The IP Storage Gateway 9200 allows both types to be connected to the same unit, where it presents them to the network as either NAS (network attached storage) or iSCSI (Internet SCSI) targets. The appliance is well engineered and built around a good-quality Supermicro motherboard, although the internal lighting arrangement is a little tacky for our liking. Connectivity options are provided by a dual-port QLogic FC card, while the motherboard's dual Ultra320 SCSI channels are routed through to the backplanes at the rear. Network features abound: the motherboard has a pair of Intel Gigabit ports, but you also get an Intel dual-port Gigabit card. All ports can be used to present iSCSI targets to the network and they can also be joined together in a virtual connection as load-balanced and failover teams.

Initial configuration starts with a visit to the colour LCD and control pad on the appliance. Here, you need to provide a static IP address to the first Ethernet port on the motherboard. All further configuration is carried out from the simple Java-based remote management console. It's designed to manage multiple appliances, so after selecting one and logging into it, you're faced with a row of large icons offering shortcuts to the various storage-related functions. An Explorer-style tree menu provides access to storage resources, and each one is accompanied by a window to one side with a list of options for the selected resource. All storage adaptors installed in the appliance are displayed, and expanding them shows all devices connected to them. If the attached disk array has integral RAID, you'll see the logical

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drives as opposed to physical units.

We found it easy to create iSCSI targets. You simply choose a physical or logical disk and take ownership. The process is facilitated nicely by wizards that help you to create new storage targets and assign an IQN to them. You add the storage devices to the iSCSI target and then select one of the Gigabit interfaces to act as a portal. The target then has to be enabled, after which you can log onto it from your initiator. Security features are good, as you can restrict access to specific initiators or IP address ranges and enforce CHAP authentication. NAS file shares are a tougher nut to crack, though, and the process isn't helped by the fact that the management interface reveals too much of the underlying Linux kernel. After selecting a storage volume, you create a file system on it, add a mount point, create an SMB/CIFS share and enable it. Security options include AD authentication, but since the appliance uses the standard Unix file-journalling system, it doesn't offer features such as ACLs (access control lists).

To test performance, we called up a Dot Hill SANnet II 200 FC disk array, which had dual redundant controllers, each with four 2Gb/sec FC ports and RAID controllers with battery-backed cache memory. We used six 146GB Seagate Cheetah FC hard disks and configured them as JBODs. The SANnet II was connected to the 9200 using both 2Gb/sec FC ports, and we configured three drives to appear on each of the FC ports. Had we opted for a RAID array, the logical drives would have appeared to the 9200 instead. It's worth noting that the 9200 can manage RAID arrays itself, but as these will be implemented in software there'll be a corresponding hit on performance.

The appliance was linked to a Gigabit Ethernet network and we used a dual-Xeon server running Windows Server 2003 and Microsoft iSCSI initiator 2. To test raw throughput, we employed Iometer configured with two disk workers, 64KB sequential read transfer requests and ten outstanding I/Os. We found NAS performance to be good, with the appliance returning a speedy 80MB/sec with a SMB file share mapped to the server. We then created a single iSCSI target and logged the server onto it, after which Iometer reported a fast 97.5MB/sec throughput. This is well above average and beaten only by NetApp's FAS3020, Adaptec's Snap Server 18000 and, of course, the EqualLogic PS300e.

The 9200 is an interesting storage solution that allows all manner of SCSI and FC disk arrays to be mixed together and presented as iSCSI and NAS storage. It would also be a good choice where companies want to maximise the usefulness of legacy disk arrays, although the management interface needs more work to make it easier to use.