On Nov 8, 2005, at 00:13 , Neil Brown wrote:
On Monday November 7, marvin@xxxxxxxx wrote:
I've got a simple setup with three IDE drives where two disks share a
30mb RAID1 partition for /boot and all three share a 590GB RAID5
array for /
My mdadm.conf looks like this:
DEVICE partitions
ARRAY /dev/md1 level=raid5 num-devices=3 UUID=4b22b17d:
06048bd3:ecec156c:31fabbaf
devices=/dev/hda3,/dev/hdc3,/dev/hdg2
ARRAY /dev/md0 level=raid1 num-devices=2
UUID=7d5c8486:35fff755:f5d34fc2:a12f1f81
devices=/dev/hda1,/dev/hdc1
You should remove the "devices=" sections. They aren't causing a
problem in this case, but they could if you happened to change the
name of a device (plug it in somewhere different).
The UUIDs check out with the devices, and indeed /dev/md0 works
fine. /dev/md1 used to work perfectly, but read on :-p
All the raid partitions are type 0xfd RAID auto-detect.
Are you sure? Really really sure? Particularly hdc3. What is it's
type. Could you
fdisk -l /dev/hdc
just to convince me? Because your problem REALLY looks like the
partition type isn't 0xfd...
You gave lots of detail, which is excellent, and from all that detail,
I cannot see any other possible explanation.
Unfortunately I'm sure;
Device Boot Start End Blocks Id System
/dev/hdc1 1 6 48163+ fd Linux raid
autodetect
/dev/hdc2 7 30 192780 82 Linux swap /
Solaris
/dev/hdc3 31 36481 292792657+ fd Linux raid
autodetect
The table is identical to the one hda uses.
Originally I created the RAID partitions with the Debian Sarge
installer - and it's worked great up until I replaced hdc.
I just did a little more googling and found this:
http://groups.google.com/group/linux.debian.maint.boot/browse_thread/
thread/c8d20fc20603b120/46104bd9670312b6?lnk=st&q=raid+dropping
+partition+boot&rnum=3#46104bd9670312b6
which describes a Debian installation on a drive structure similar to
mine(except I don't use LVM on top of the RAID5).
It states that it could be a problem having more than one primary
partition for software raid on a drive because mdadm would write a
raid superblock to the disk device and cause chaos.
I checked the drives, and it looked like this:
mdadm: No super block found on /dev/hda (Expected magic a92b4efc, got
00000000)
mdadm: No super block found on /dev/hdc (Expected magic a92b4efc, got
00000000)
mdadm: No super block found on /dev/hdg (Expected magic a92b4efc, got
70e7710e)
So I think I should be safe. Still, all partitions on the drives are
primary partitions. Could that be the explanation?
Regards, Troels
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