Nexsan unit sets new capacity standard, but Fibre Channel, SCSI systems have edge in performance.
Nexsan Technologies ATAboy2 (click here to see the ATAboy2
) is an inexpensive RAID solution that small and medium-size businesses with large storage appetites should welcome with open arms.
The ATAboy2 takes advantage of the lower cost and high capacity of ATA (Advanced Technology Attachment) drives to create RAID units with impressive cost efficiency.
In tests at eWeek Labs, we found that the ATAboy2, which shipped earlier this month, effectively fills the void between expensive SCSI and Fibre Channel disk solutions and the inexpensive ATA RAID systems that are commonly found in workstation-class computers.
Although we wouldnt recommend this unit as a replacement for high-performance Fibre Channel storage units (such as those used to run transaction-intensive databases), IT managers who need raw capacity and want more bang for their storage buck should gravitate to the ATAboy2.
The test unit was priced at $13,100, and it packed a whopping 1.3 terabytes of usable storage space (running RAID 5) in a modest 5.25-inch rack unit.
The ATAboy2 uses ATA as the drive interconnect, but to connect the unit to servers, IT managers have the option of using SCSI, Fibre Channel or even iSCSI.
The ATAboy2 can support eight LUNs (logical unit numbers) per host: The back of our particular test unit had four Ultra160 SCSI channels.
Going the SCSI or Fibre Channel hard drive route, it would be nearly impossible to get the same capacity without spending close to double the cost of the ATAboy2. This is because SCSI drives are far more expensive than ATA drives.
The ATAboy2 has management software that is comparable with (but not quite as good as) the software we have seen running on other RAID units. The management software is Web-based and is served up from an embedded Web server.
Using the management software, we were able to create, expand and delete volumes and configure our RAID array.
When it comes to hard drive rotational speeds, ATA drives are vastly inferior to Fibre Channel and SCSI hard drives. The ATAboy2s drives have the ability to spin at 7,200 rpm, which trails far behind current 15,000-rpm SCSI drives. This lag will probably ensure that applications that need quick access to data will run far better on SCSI or Fibre Channel RAID units.
In our tests, the ATAboy2 performed reasonably well, and we believe it will be a good choice for file storage or for archiving data.
Using Intel Corp.s Iometer benchmark, which measures storage throughput and I/O performance, we found that when doing a throughput-intensive test (reading and writing sequential data using large request sizes), we could get roughly 45MB-per-second throughput. We believe we would have gotten significantly better aggregate performance using the extra channels (we hooked up our ATAboy2 to a single Dell Computer Corp. PowerEdge 4400 server), but even then, the ATAboy2 will not win any footraces with high-end RAID units.
The ATAboy2 topped out at roughly 4,300 I/O operations per second running a sequential read test with a 512-byte request size.
Our ATAboy2 unit came with only 128MB of cache (although this is expandable to 512MB), and we believe that this cache size limited the performance we saw.
Another feature that may have contributed to our less-than-spectacular performance numbers is the fact that the test ATAboy2 configuration had only a single RAID controller on board. In contrast, most enterprise RAID units have dual controllers with cache coherency to make sure that there is no data corruption in the event of a RAID controller failure.
Future versions of the ATAboy2 will come with a redundant controller option, according to Nexsan officials.
The lack of LUN masking capabilities is a slightly negative omission, but in many storage area networks this should not be an issue because current Fibre Channel switches from vendors such as QLogic Corp. have zoning and LUN masking capabilities to take care of storage allocation management.
Nexsan also sent us its InfiniSAN 2 software to effectively turn our ATA- boy2 array into a backup solution. The InfiniSAN 2 software was easy to use, and it allowed us to quickly back up our servers data to the ATAboy2 RAID unit.