Wednesday, November 9, 2011

Hitachi Deskstar + RocketRAID 232x

Spent the morning tracking down a stupid RAID problem, so hopefully this helps someone...

I use RocketRAID 2320 cards as HBAs in a few Ubuntu servers. I use software RAID (mdadm), so no need for the RAID features.

The trick to using the rr232x as an HBA is to configure each drive as a separate single-disk JBOD "array" in the RocketRAID BIOS. In the servers I've set up before, I've used eight Western Digital (Green) 1.5 TB and 2.0 TB drives, did the JBOD thing, and they appeared to the OS without issue.

My new server has 12 3.0 TB Hitachi Deskstars (H3IK3000), and when I installed the rr232x driver, I saw no drives. The RAID card could see the drives, and the OS could see the RAID card, but the OS couldn't see the drives.

When the drives that had been attached to the RR2320 were plugged directly into the motherboard, I noticed that they didn't spin up. The OS saw them and tried to talk, but timed out and gave up. Identical drives not exposed to the RR2320 worked fine.

There turned out to be two problems:

  1. The staggered spin-up feature of the RR2320. Apparently not compatible with these Deskstars, when enabled it flips a bit telling the drives not to spin up at all. The solution is to enable-then-disable the staggered spin up setting (Settings menu in the BIOS utility).
  2. The RR2320 just doesn't seem to like H3IK3000s. Solution: run the drives in "Legacy" mode rather than as JBOD arrays, a tidbit I picked up from here.
To run in Legacy mode, put an empty partition on a drive (plug into mobo, "mklabel" and "mkpart" in parted). The RR2320 will ignore it and pass it through to the OS.

  1. Enable-then-disable staggered spin-up
  2. Plug each drive into the motherboard and fire up parted
    1. mklabel gpt
    2. mkpart (enter: null, xfs, 1, 3tb)
    3. set 1 raid on
  3. Plug drives back into the RR2320 -- should see them on boot
  4. mdadm --create /dev/md0 --raid-level=6 --raid-devices=12 /dev/sdb1 /dev/sdc1 ... /dev/sdm1
  5. mkfs.xfs /dev/md0