The ix2 supports two different ways to configure its drives. The Settings > Disks > Manage Disks > Data Protection screen (Figure 15) is where the magic happens.
You can choose Mirroring (RAID 1) where your data is transparently duplicated but your capacity is cut in half, or JBOD where multiple disks in the box are treated as one big disk. In this case, I have the box set to Mirroring so that if one of my disks fails, I won't lose any data.
Figure 15: Disk Setup
Note that ix2's drives are not designed to be user serviceable. So if one does fail, you'll need to ship it back to Iomega for replacement. The drives are formatted using ext3, so at least you can attempt data recovery on your own before shipping the product back to Iomega. But opening the case will void your warranty.
RAID 1 Fail Test
In order to see what would happen in the case of a failure, I opened the case and yanked power to one of the SATA drives while the system was up and running. The first thing I noticed was a red LED on the front panel telling me that something was wrong.
Shortly thereafter, I received a couple of emails telling me that there had been a failure. The Log file (Figure 16) also noted the problem. As expected in mirroring mode, my original data was still available and unaffected.
Figure 16: Log of failure
Next, to see how a recovery would occur, I shut the box down, replaced the cable and booted back up. When the ix2 came back up, the red LED started blinking, and I received an email telling me that a recovery was underway. While the recovery proceeded (several hours), my data was still available.
When the recovery was done, I received an email telling me that the process was complete, and the red LED stopped blinking. This automatic recovery was done well and is what you want to see with these devices. But since Iomega doesn't support user-replacement of a failed drive, you'll never see it unless you want to void your warranty.
IOzone was used to test the ix2's performance (the full testing setup and methodology are described on this page). The test unit had the latest 22.214.171.124772 2008-09-06 00:18 firmware and was tested with 100 Mbps and 1000 Mbps LAN connections.
Figure 17 shows NAS Chart rankings for the 1000 Mbps Write test, filtered to show only two-drive NASes. The bars represent the average of performance for file sizes from 32 MB to 1 GB. The ix2 ends up in the lower third with 11.5 MB/s average.
Figure 17: 1000 Mbps Average Write NAS Chart ranking
Read speed is better, ranking in the top third with a 15.6 MB/s average.
Figure 18: 1000 Mbps Average Read NAS Chart ranking
To compare the ix2 competitively, I chose the Netgear ReadyNAS Duo (RND2150), Buffalo Technology LinkStation Mini (LS-WS1.0TGL/R1) and the ix2's predecessor, the Iomega StorCenter Network Hard Drive 1TB (33872).
Figure 19 compares write performance with the products configured in either JBOD or RAID 0 with a 1000 Mbps LAN connection. The NETGEAR does consistently best across the range of large file sizes and the ix2 (34299) is the slowest once filesize hits its internal RAM size. Note that the original StorCenter Terabyte, even with half the memory, does better than the ix2.
Figure 19: 1000 Mbps Comparative Write
The ix2 does better in the read comparison, actually coming in first after the test file size meets and exceeds the NETGEAR's 256 MB of RAM.
Figure 20: 1000 Mbps Comparative ReadFigure 21 compares the ix2's write and read performance with the 1000 Mbps LAN connection. You can clearly see the performance change once the test file size is equal to or larger than the ix2's 128 MB of RAM.
Figure 21: 1000 Mbps Read Write Test
Use the NAS Charts to further explore the ix2's performance.