On Thursday April 1, donj@asaca.com wrote:
>
>
> I have been testing disk failures with RAID5. I have problems that I
> have run into that happens with raidstart and mdadm.
>
> Here is the scenario. I stop a healthy raid5. I then do either one
> of the following: I poweroff the first disk in the raid5 and remove it or
> I zero out the raid superblock on the first disk. I then go ahead and
> try to start the raid either by raidstart command or
> mdadm --assemble --run /dev/md8 /dev/sda1 /dev/sdb1 /dev/sdc1 /dev/sdd1
> /dev/sde1
When asking mdadm to assemble an array, you need to tell it what array
to assemble.
The above command essentially says "Assemble the array that /dev/sda1
is part of, using it as well as b,c,d,e".
Obviously this will fail if sda is bad.
You can discover this fact about mdadm if you read the man page.
In the section "ASSEMBLE MODE", it says:
This usage assembles one or more raid arrays from pre-existing compo-
nents. For each array, mdadm needs to know the md device, the identity
of the array, and a number of component-devices. These can be found in
a number of ways.
A little later it says:
The identity can be given with the --uuid option, with the --super-
minor option, can be found in the config file, or will be taken from
the super block on the first component-device listed on the command
line.
giving three ways. You are using the last.
If you read the rest of the man page, I'm sure you will figure out how
to do what you want, and possibly a good many other things too.
NeilBrown
>
> Both of these commands fail. I do admit when using the mdadm command I
> can get the RAID5 to start if I leave out the first disk.
>
> But when I try this same test with any other disk in the raid set (so any
> disk other than disk 0 ) the command raidstart works and I
> assuming mdadm command would work as well. That is what I would like
> to happen with disk0 as well. Is there anyway to start
> a degraded raid set consistently without having to manually figure
> out which disk failed?
>
>
> Any way to make this work? If it is a simple fix I could do it myself
> if someone could point me to right direction or maybe there is a latter
> version of the mdadm command that this is not a problem. Any one ?
> Any ideas?
>
> I'm running linux 2.4.22 kernel with mdadm - v1.3.0 - 29 Jul 2003.
>
> Thank You
>
>
>
>
>
>
>
>
>
>
> =====
> Don Jessup
> Asaca/Shibasoku Corp. of America
> 400 Corporate Circle, Unit G
> Golden, CO 80401
> 303-278-1111 X232
> donj@asaca.com
> http://www.asaca.com
> -
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
-
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
