Friday, November 23, 2012

Pulling a RAID drive

My development environment is a bunch of virtual machines (VMs) running in Hyper-V on a Windows 2008 R2 Server. The server is a Dell Precision T7600 (details in previous posts). It has a separate RAID controller card with a battery that’s started showing warnings about not charging due to high temperature.

The RAID has 4 SAS drives configured in RAID 10, so a single drive failure should be covered because each physical drive is mirrored on to another physical drive. So this consumes half your total drive space, but means you can survive a drive failure (in theory).

However, does it work? What would it even look like? Long story short: I just yanked a drive out while the host was still running.

Everything was smooth. The Hyper-V host didn’t event wobble. The MegaRAID software gave me an alert, so I launched the Storage Manager where it gave me a bunch a details. I pushed the drive back in and it began rebuilding the drive – presumably it’s copying the data from the mirror back over. It reckons this will take about 2 hours, but the system is still usable while it does this. Update: It actually took 9 hours to rebuild the array.

Here’s a screenshot of the Storage Manager during the rebuild (click to enlarge):

RAID rebuild following drive hot drive removal

No comments: