Jimmy's weblog


IBM x3100 M4 with ServeRAID C100: Testing Debian Compatibility

Filed under: — jimmy @ 2:22 pm

When IBM announced their new entry server I first checked the specs and found out, that they are going back to fakeraid controllers in the low cost machines. I was really glad a couple of years ago when those controllers disappeared but now they are back again :( Furthermore it first seemed, that the controller was not supported in the kernel of debian squeeze. So I ordered one of the first x3100 M4 to find out myself. It turned out, that there’s absolutely no problem with the squeeze kernel (Didn’t find those reports, who said that the controller is not detected, again, so I hope this false information is lost forever or at least hard to find).
Depending on the BIOS setting (modus AHCI or RAID) the controller shows up as:

00:1f.2 SATA controller: Intel Corporation Cougar Point 6 port SATA AHCI Controller (rev 05)


00:1f.2 RAID bus controller: Intel Corporation 82801 SATA RAID Controller (rev 05)

Although I already wasted a lot of time in my life with fakeraid controllers I decided to test the ServeRAID C100, too. Here are the lessons I’ve learned:

  • Never create the RAID in the OS because you might choose the wrong format and thus you will not see the RAID in the BIOS or IMM2 and lose the ability to monitor the health status. Create it in the BIOS or with the CLI tool.
  • If you want to install with the debian installer then you need to add option “dmraid=true” in expert mode
  • grub2 in squeeze has a bug that prevents installation on fakeraid (dirty hack: install grub from sid)
  • Booting from dmraid is broken in Debian: Bug #603319 with a dirty hack
  • I hope this posting will help you, if you really need to configure such a machine. It’s also possible and supported to upgrade the x3100 M4 with a HW-RAID controller, e.g. ServeRAID M5015 (you need the Hot-Swap Backplane, too).


    Growing Hardware RAID-5 with arcconf

    Filed under: — jimmy @ 8:26 pm

    Maybe you read my previous post “Growing Hardware RAID-5 with LVM by adding a physical disk” where I described how to add another disk to a RAID-5 with the MegaCLI tool. For older ServeRAID controllers you have to use the arcconf tool instead, e.g. ServeRAID-8k, which was shipped in the first x3650 models. There’s plenty of documentation about arcconf but how to resize a raid was hard to find. The MODIFY command is used for resizing and let’s assume that we have 3 disks in the array and add another one (same as in my previous post)

    ./arcconf modify 1 from 1 to MAX 5 0 0 0 1 0 2 0 3

    The syntax of arrconf is:

    ./arcconf MODIFY <Controller#> FROM <LogicalDrive#> TO [Options] <Size> <RAID#> <CHANNEL# DRIVE#> [CHANNEL# DRIVE#] [noprompt]

    So in our case it was Controller# 1 and LogicalDrive# 1 and MAX means to use all capacity that will be available. Raidlevel will still be level 5 and the harddisks are [0 0], [0 1], [0 2] and the new [0 3].
    To watch the status of the raid migration, use

    ./arcconf getstatus 1

    JFYI: To add another 146 GB SAS (15k) to the raid it took about 12 hours to rebuild the array.