In Q3 we added 79 HGST 12TB drives (model: HUH721212ALN604) to the farm. While 79 may seem like an unusual number of drives to add, it represents 'stage 2' of our drive testing process. Stage 1 uses 20 drives, the number of hard drives in one Backblaze Vault tome. That is, there are are 20 Storage Pods in a Backblaze Vault, and there is one 'test' drive in each Storage Pod. This allows us to compare the performance, etc., of the test tome to the remaining 59 production tomes (which are running already-qualified drives). There are 60 tomes in each Backblaze Vault. In stage 2, we fill an entire Storage Pod with the test drives, adding 59 test drives to the one currently being tested in one of the 20 Storage Pods in a Backblaze Vault.

To date, none of the 79 HGST drives have failed, but as of September 30th, they were installed only 9 days. Let's see how they perform over the next few months.

A New Drive Count Leader

For the last 4 years, the drive model we've deployed the most has been the 4TB Seagate drive, model ST4000DM000. In Q3 we had 24,208 of this drive model, which is now only good enough for second place. The 12TB Seagate drive, model ST12000NM0007, became our new drive count leader with 25,101 drives in Q3.