Re: Software RAID problem - disks names change in case one fails
On Fri, 9 Sep 2005 initiators@free.fr wrote:
> I'm testing a server before I put it in production, and I've got a problem with
> mdraid.
>
> The config:
> - Dell PowerEdge 800
> - 4 x 250 Go SATA attached to the mobo
> - /boot 4 x 1 GB (1 GB available)in RAID1, 3 active + 1 spare
> - / 4 x 250 GB (500 GB available) in RAID5, 3 active + 1 spare
> No problems at install, and the server runs OK.
>
>
> Then I stop the server and remove /dev/sdb to simulate a hard disk failure that
> has caused a crash and a reboot.
purrfect test .... and do the same for each disk ....
it is pointless to have 1 spare disk in the raid array
- have you evern wondered about other folks that try to build a sata-based
raid subsystem ??
- how did their sata pass the "failed disk" test if it
reassigns its drive numbers upon reboot
> With the second disk removed the disks names are changed,
exactly.... that is the problem with scsi
- pull the power cord from it to simulate the disk failure
or pull the sata cable ...
- in either case, if the disk drives rename itself, based on
who's alive, raid won't work to boot after the failed disk
( but it will stay running until its booted )
> the 3rd disk /dev/sdc
> becomes /dev/sdb and the 4th disk (that was the spare disk) /dev/sdd becomes
> /dev/sdc.
thta's always been true of scsi
> During the boot process md detects that there is a problem, but then complains
> it can't find the /dev/sdd spare disk and the boot process stops with a kernel
> panic error.
exactly
c ya
alvin
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