RAID Fail Test
As shipped, the NMH405 only has a single drive, but it will support RAID 1 (mirroring) as well as storage expansion (JBOD) modes with a second drive added. So I decided to test RAID 1 expansion and failure. Though the documentation is a bit sparse, the manual and user interface says that the second drive must be the same size or larger than the original in order to configure the Media Hub for RAID 1. It also warns that you should back up all of your data to another device, since creating a RAID 1 configuration will essentially wipe the data from the original drive as well as the second drive.
I first shut down the device and installed a 1 TB Seagate drive into the open slot. After rebooting, I logged into the Configuration page and selected the Increase Protection option under the Disk tab. After selecting the option, the device became unavailable for a period of time, and then rebooted.
After the reboot, the Media Hub came back online, and the Import tool installed on two of my test computers immediately started to upload content to the Media Hub, since all of the data on the Media Hub had been wiped. It took some period of time to re-copy the data and for the RAID to synchronize. During the synchronization process, a progress bar is available in the user interface, and the device is available for user access.
Once the drive had synchronized, the disk page of the configuration menu showed the RAID as “OK” as shown in Figure 19.
Figure 19: Media Hub reconfigured for RAID 1
I did note, however, that the automatic backup job created when I installed NTI Shadow failed, because the target directory (\\mediahub\backup\HPMEDIA) no longer existed. The default share of \\mediahub\backup was re-created, but not the directory corresponding to my computer name. Once I manually re-created the directory, the backup ran normally.
Next, I decided to test the fault tolerance of the device. I powered down the Media Hub and pulled drive 2 to simulate a failure. When I rebooted, the device came back up with all of the original data, but was just running on drive 1.
I was disappointed that neither the front panel LCD, nor the home page of the user interface indicated that the device was operating with a degraded RAID status. I had expected the LCD to show an alert, but even the status choices on the LCD didn’t show a degraded RAID. However, the disk configuration page, shown below in Figure 20, did show the “missing” drive and the RAID status as degraded.
Figure 20: Degraded RAID 1
I wrote some additional files to the Media Hub and then powered down so that I could re-install the drive that I had previously pulled. I re-installed the disk and rebooted the device. The Disk configuration page recognized the drive and the option to “Rebuild” appeared as shown in Figure 21.
Figure 21: RAID degraded, but second drive recognized with option to rebuild
After clicking on Rebuild and acknowledging the notice shown in Figure 22, the RAID started to rebuild.
Figure 22: RAID rebuild notice
During the rebuilding process, shown in Figure 23, the Media Hub remained online and available. I copied files to the Media Hub during the rebuild process which, based on the elapsed time and the percentage complete, looked like would take about 2 hours.
Figure 23:Media Hub during RAID synchronization
The RAID rebuilding process was relatively smooth and similar to what we have found on other RAID 1 products. I would have liked to see a more visible notification, however, of degraded status on either the front panel LCD or even the NMH's home page. It would also be nice if the NMH supported RAID migration and expansion, so that you wouldn't have to scramble to find a place to temporarily park your data when adding a second drive.