Although network storage options at the enterprise level are becoming more varied, Fibre Channel (FC) is still the top choice where performance is a key requirement. Its biggest drawback has traditionally been ridiculously high prices but the ATAbeast from Nexsan puts a new spin on this technology, as it offers an unbelievably high storage density, packs it into a low-profile FC equipped chassis and delivers it at a comparatively low price.
FC and SCSI hard disks get the elbow in the search for reduced costs as the appliance supports ATA drives and the 4U chassis has room for an incredible forty-two hard disks. There is no access to the drives from the front as they are all located underneath the top panel and mounted vertically into Nexsan’s proprietary controller board. Access isn’t so good as the chassis must be pulled halfway from the rack cabinet and ten screws removed to release the top panel. However, from this point on the drives are easily accessible and the controller board supports full hot-swap capabilities. The price includes a full compliment of 250GB ATA/100 Hitachi Deskstar drives giving a total capacity of 10.5TB. However, with the latest 400GB models a single ATAbeast can deliver 16.8TB and a mouthwatering 168TB per 42U rack cabinet.
Good fault tolerance includes three 450W hot-swap power supplies and a pair of hot-swap RAID controller modules. The latter each come with 450MHz MIPS RISC processors, 512MB of cache memory plus a battery backup pack and support RAID levels -0, -1, -10, -4 and -5. Each controller also sports a pair of FC SFP ports supporting both 1Gbit/s and 2Gbit/s operations. A serial port on each controller is for local management while a 10/100BaseTX port provides access to the controller’s web server. An unusual arrangement is that the controllers operate independently of each other and are assigned specific bays in the drive enclosure. Each drive is factory-tested by Nexsan prior to delivery and verified for a particular controller so you need to pay close attention to the manual and the map on the underneath of the lid when installing the drives to make sure they go in the correct slot groups.
Two installation routes are on offer as you can use a local serial connection to the well designed CLI or point a web browser at the controller’s default IP address for remote management. The latter’s interface is also easy to use and provides good access to all components. Wizards are in abundance and you can start off by allowing the system to create multiple RAID-5 arrays with all available drives and map the volumes to both FC ports on each controller. Note that the ATAbeast doesn’t support JBODs but it’s easy enough to select drives, pick a RAID array and choose an FC port to map them to. There’s plenty of operational information from the home page, as you can view a complete rundown on drives, arrays, controllers and power supplies and if any faults are detected the appliance will sound an internal alarm and can send alerts to one email address. Drive bays are represented by a simple matrix which uses animated graphics so you can see individual drive status at a glance. As the controllers operate independently, each runs their own internal web server but you only need to load a single browser as Nexsan’s WorldView allows you to swap easily between each one.
With the ATAbeast hooked up to our test SAN comprising QLogic’s SAN Connectivity Kit we watched the ATAbeast deliver an impressive performance. We created four dual-disk RAID-0 striped arrays and assigned each to a different FC port. With Iometer at the helm we saw a single direct attached Windows Server 2003 system return average transfer rates of 181Mbytes/sec which isn’t far off wire speed for FC. Adding another 2003 server to the second controller saw this ramp up to 361Mbytes/sec whilst a full compliment of four servers each directly attached to separate FC ports delivered an impressive cumulative total of 724Mbytes/sec. There is a small penalty to pay with ATA drives as the ATAbeast was around seven per cent slower than the FC drives in Chaparall’s Rio eXP.
Along with top management facilities and fault tolerance the ATAbeast scores highly for sheer storage capacity as you’re unlikely to find anything else that can match it at the price point. Nexsan targets it particularly as a high-capacity, high-performance replacement for tape based backup systems - a job the ATAbeast clearly has the credentials for.
If server room floor space is at a premium you won’t find a higher storage density than that offered by the ATAbeast, as FC and SCSI based arrays can’t come close to this. Using ATA drives does bring a small drop in comparative performance but the storage potential, and price, more than makes up for this.