Product Reviews

Adaptec's acquisition of Snap Appliances in July 2004 gave the company a strong platform to build its new storage portfolio. Its range covers small businesses to the enterprise, allowing it to compete with the likes of HP. Representing the flagship of the Snap Server NAS appliances, the latest 18000 aims to deliver a high capacity and top performance, with plenty of expansion options.

We've seen more than a few NAS appliances in the PC Pro Enterprise labs and we can safely say the 18000 is the best built yet. This 2U-rack chassis delivers an excellent hardware specification and yet again we see Serial ATA taking over from SCSI as the interface of choice in the NAS market. The price includes eight 250GB Maxtor SATA drives fitted in solid hot-swap carriers. These are accessed simply by pulling forward the front cover and flipping it over to reveal the hot-swap bays behind.

The 18000 looks good from the inside as well, with nine hot-swap cooling fans sitting behind the disk backplane. Operational noise levels are reasonably low, although the 18000 isn't something you'll want in the same office as you. The motherboard uses a large riser card assembly, with one PCI-X slot occupied by an eight-port Marvell SATA controller card that provides 512MB of battery-backed NVRAM. However, it doesn't manage RAID arrays, as this function is carried out in software by the OS. A pair of Intel gigabit Ethernet adaptors is provided, and power fault tolerance comes into the picture with hot-swap supplies as well. Storage expansion potential is good, as you can connect up to seven 4TB Snap Disk SD30SA arrays to the 18000 using a single Fibre Channel host bus adaptor, allowing storage to be increased in easy stages up to a massive 30TB.

Installation kicks off with a visit to Adaptec's Snap Server Manager, which runs a discovery routine and displays any appliances it encounters on the network. Pick one from the list and you can administer basic functions directly from the Manager utility or move to a browser link for further remote configuration. The appliance also has a large, backlit LCD panel at the front that shows the name of the unit and its IP address. It also provides access to a basic event log.

The Snap Server appliances are all based on a Linux kernel, with the 18000 running the

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latest GuardianOS. This provides a smart management interface that's common across all these products. It offers easy access to all functions, and the appliance supports Windows, Unix, Linux and Macintosh client access. Security is also very good, as the OS supports features such as user, group and NT domain authentication plus Windows Active Directory and Unix NIS (network information services), while remote browser management access can be secured over HTTPS. The main competition to Adaptec's GuardianOS comes from Windows Storage Server 2003 and we found they both offer an equally good range of features.

Backup options for the 18000 are extensive, as it offers volume snapshots that are stored in native format, so you can recover files using just Windows Explorer, and you also get the standard Symantec DataKeeper tool for securing workstation data to the appliance. The optional Server-to-Server feature allows selected appliances to synchronise their contents with other Snap Servers, although note this isn't true mirroring since it only runs at scheduled times and not in real-time. The 18000 can also be integrated into third-party backup products, with Adaptec offering agents for all the key software vendors including Computer Associates, Symantec, Legato and BakBone. Local anti-virus protection is provided as standard by CA's eTrust Antivirus, which is integrated on the appliance and accessed from the GuardianOS interface.

iSCSI is growing in popularity (see iSCSI - behind the hype, p193), so it's no surprise that the 18000 supports this protocol. A wizard is provided to help create iSCSI targets, allowing you to pick a volume, decide how large the iSCSI disk should be, enable write cacheing and implement CHAP authentication. The appliance also supports iSNS servers, and you can block access from multiple iSCSI initiators.

To test iSCSI performance, we used a dual Xeon Windows Server 2003 system with Microsoft's Software Initiator 1.06 installed and logged onto a single 25GB target. We configured the open-source Iometer with two disk workers, ten outstanding I/Os and 64KB sequential read operations. For raw throughput, it returned an amazing 107MB/sec, which is currently the fastest performance we've seen from a single initiator connection to one iSCSI target. However, using the software initiator does hit local processing hard, with the test generating about 45 per cent CPU utilisation. We reran the same test using an Adaptec 7211C iSCSI host bus adaptor and saw similar speeds, but at a cost of only 7 per cent local CPU utilisation.

The Snap Servers may have been through a number of owners, but they've lasted the course and continue to offer a solid product line. The 18000 moves Adaptec firmly into the enterprise storage market and delivers a fine range of features that will give the latest Windows-powered appliances a good run for their money.