As mentioned previously, the S402 supports various RAID modes. Figure 14 shows the menu where the mode can be specified.
Figure 14: TS-S402 RAID Specification
In this case, I have the device configured in RAID1 mode where data is mirrored to each drive to protect against disk failure, the downside being cutting my total disk capacity in half. As you can see, the other RAID modes supported are 0, where the data is spread across two drives for additional performance but no
When problems do occur in the system, the S402 has an
Figure 15: TS-S402 Alert Setup
To test the RAID recovery feature and the alert mechanism, I opened up the case and yanked the cable off one of my two drives. I expected to see some immediate reaction, but I saw nothing. Even the two disk LEDs remained lit. When I checked my email, I had nothing, but a check of the logging feature of the box (Figure 16) showed that the removal had been detected.
Figure 16: TS-S402 Disk Failure
While the disk was out, I could access my data as if nothing had happened, which is the benefit of using RAID 1. To check out recovery, I shut the system down (since hot-swapping is not supported),
Once again, I had to dig a bit to find out what was going on. Figure 17 shows the log that indicated that the drive rebuild was automatically started and underway.
Figure 17: TS-S402 RAID Recovery
While the rebuild was underway, my data was available as before, but with reduced performance. It was nice to have the automatic rebuild, but I expected to get more notification, e.g. blinking lights, buzzers, or email (more on this later) telling me that something had gone badly wrong. Since I only had 80GB disks in the system, my rebuild time was fairly short - about 30 minutes.