RAID Configuration

You may have noticed that none of the Status screens provide any indication of drive or volume status. For that, you need to go to the Storage menu, Disks screen (Figure 9) where you would first check to see whether all of the drives that you had installed are present and accounted for. Clicking on the links in the Status column brings up a screen providing a few bits of SMART info including Power On Hours, Reallocated Sector Count and Current Pending Sector.

Note that the Disk Power Management selector is inoperative in the 1.00.03 firmware used for this review. Also absent is the ability to shut down and wake up the 5200 on schedule. Some readers have asked me to add a check to see what happens when power is restored after a sudden power failure. So I pulled the plug with the 5200 running, waited a bit, plugged it back in and found that it stays powered off.

Figure 9: Storage > Disks screen

Configuring the 5200's drives for operation requires a visit to the RAID screen. Figure 10 shows the screen just after I initiated a RAID 6 build. You can see that RAID 6 cuts available capacity almost in half, but the build time wasn't really 5187 minutes (86 hours!). Although the 5200 is available for use (at reduced performance) during RAID array build, I found it took around 4 hours to completely build all RAID configurations except RAID 6, which took more like 6+ hours.

Figure 10: Storage > RAID screen

Figure 11 shows the controls available on the RAID Configuration screen. I used all five drives in my RAID 6 configuration, but you only need to use four. (You can only use a maximum of four drives for RAID 10.) The Spare checkboxes and Add Spare button let you assign a drive to be automatically swapped in, should one drive of your RAID array fail. Thecus' documentation says that RAID 6 and 10 can sustain two drive failures, while RAID 1 and 5 can have only one drive go bad and keep running.

Figure 11: Storage > RAID configuration screen

To test this with the 5200 configured in RAID 6, I pulled two drives with about 10 seconds' pause between. The front panel LCD display quickly identified the "bad" drives and informed me that the system was running "degraded". When I reinserted the drives, the front panel display properly reported the changes and kept me updated on the rebuild progress.

I wish I could say that the failure information presented in the web GUI was as easy to find and informative, but it wasn't. You get no indication of trouble upon logging in and checking all the Status menus also comes up empty. You'll need to navigate to the Storage > RAID menu to see what's wrong or pick through the three separate logs.

In addition to being able to designate a RAID spare, the 5200 also supports RAID Migration and Expansion. RAID Migration is supported for RAID 0, 1 and 5 arrays and allows changing the number of drives or RAID level. Possible migration paths are automatically listed, such as changing a RAID 1 array with 2 drives to RAID 5 with 5 drives.

RAID Expansion allows you to substitute larger drives for smaller without having to completely kill an existing array and rebuild from scratch.

Note that, unlike a normal RAID build, all file services (SMB/CIFS, AFP, NFS, FTP, etc.) are not available during RAID Migration and Expansion. And if you lose power during either operation, your data will be no more. So plugging the 5200—or any other NAS for that matter—into a UPS is highly recommended.

Tags: NAS, RAID, Thecus,

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