This week it was finally time to put our old EMC Avamar backup/DR grids out to pasture, and while I had removed most of the configurations from them already, I still needed to sanitize the disks. Unfortunately, a quick search of support.emc.com and Google revealed that “securedelete” operations on Avamar grids require EMC Professional Services engagements. Huh? I want to throw the thing away, not spend more money on it…
A few folks offered up re-initializing the RAID volumes on the disks as one way to prepare for decommissioning. That’s definitely one option. Another is to wipe the data from within, which has much of the same result, but provides a degree of detailed assurances that the PowerEdge RAID Controller doesn’t give (unless your PERC can be configured for repeated passes of random data).
Totally a side note: when I started this, I had the misconception that this method would preserve the OS and allow a second-hand user to redeploy it without returning to the EMC mothership. As you’ll note below, one of the paths we wipe is the location of /home and the rest of the OS. :x
Under the covers, Avamar is stripped down Linux (18.104.22.168-0.17-default GNU/Linux, as of Avamar 7.1), so that provided the starting point. The one I chose and that I have running across 10 storage nodes and 30 PuTTY windows is “shred”.
Shred is as simple as it sounds. It shreds the target disk as many times as you want it. So for Avamar, how many disks is that?