atacontrol raid1 vs. gmirror

[Jon Simola]

On 6/11/05, Paul Mather <paul at gromit.dlib.vt.edu> wrote:

> I found array rebuilding to be troublesome on atacontrol RAID

Some bits from the in-house documentation I've been writing. I've
tested this on multiple occasions on my 1U Supermicro SATA boxes, so
might possibly be interesting for someone.

    * RAID setup: (If required, FreeBSD only)
      - ensure that the drives are probed as ad4 and ad6 like:

      ad4: 76324MB [155072/16/63] at ata2-master SATA150
      ad6: 76324MB [155072/16/63] at ata3-master SATA150

      - if they do not probe correctly, check the BIOS settings above
      - perform a minimal install of FreeBSD 5.3 (do not worry about
network or anything)
      - reboot from the installed OS and login as root
      - Run the command "atacontrol create RAID1 ad4 ad6" to create the raid set
      - Reboot and reinstall the OS, choosing ar0 as the drive, which
should probe like:

      ad4: 76324MB [155072/16/63] at ata2-master SATA150
      ad6: 76324MB [155072/16/63] at ata3-master SATA150
      ar0: 76324MB [9730/255/63] status: READY subdisks:
      disk0 READY on ad4 at ata2-master
      disk1 READY on ad6 at ata3-master

Minimal Survival for FreeBSD software RAID1 sets

    * Read the atacontrol man page
    * atacontrol status ar0 - to check the status
    * atacontrol detach 2 - to detach ad4 if failed (again, use 3 for ad6).
      The SATA disks in the 5013C-T chassis are hotswappable, so it
can be pulled once detached.
    * atacontrol attach 2 - to reattach ad4 once replaced
    * atacontrol addspare ar0 ad4 - to add the replaced ad4 as a spare
on the RAID set
    * atacontrol rebuild ar0 - to rebuild the mirror 

-- 
Jon Simola
Systems Administrator
ABC Communications