I have done some more testing in an attempt to gather more data, and here
is what I have seen when testing different kernel options.
When booting with my normal kernel options I get the following md output
during the boot:
(raid=noautodetect md=0,/dev/sdb1,/dev/sdc1 md=d0,/dev/sdb2,/dev/sdc2)
-----
md: Skipping autodetection of RAID arrays. (raid=autodetect will force)
md: Loading md0: /dev/sdb1
md: bind<sdb1>
md: bind<sdc1>
raid1: raid set md0 active with 2 out of 2 mirrors
md0: unknown partition table
md0: unknown partition table
md: Loading md_d0: /dev/sdb2
md: bind<sdb2>
md: bind<sdc2>
raid1: raid set md_d0 active with 2 out of 2 mirrors
md_d0: p1 p2 p3 p4
md_d0: p1 p2 p3 p4
-----
Everything is well and boots fine.
If I change try to use autodetect but still keep the md= definitions:
(raid=autodetect md=0,/dev/sdb1,/dev/sdc1 md=d0,/dev/sdb2,/dev/sdc2)
-----
md: Autodetecting RAID arrays.
md: Scanned 4 and added 4 devices.
md: autorun ...
md: considering sdc2 ...
md: adding sdc2 ...
md: sdc1 has different UUID to sdc2
md: adding sdb2
md: sdb1 has different UUID to sdc2
md: created md1
md: bind<sdb2>
md: bind<sdc2>
md: running: <sdc2><sdb2>
raid1: raid set md1 active with 2 out of 2 mirrors
md: considering sdc1 ...
md: adding sdc1 ...
md: adding sdb1 ...
md: created md0
md: bind<sdb1>
md: bind<sdc1>
md: running: <sdc1><sdb1>
raid1: raid set md0 active with 2 out of 2 mirrors
md: ... autorun DONE.
md: Loading md0: /dev/sdb1
md0: unknown partition table
md: couldn't update array info. -22
md: could not bd_claim sdb1.
md: md_import_device returned -16
md: could not bd_claim sdc1.
md: md_import_device returned -16
md: startind md0 failed
md: Loading md_d0: /dev/sdb2
md: could not bd_claim sdb2.
md: md_import_device returned -16
md: could not bd_claim sdc2.
md: md_import_device returned -16
md: starting md0 failed
-----
In that case boot eventually fails with "mdadm: no devices found for
/dev/md_d0".
Finally I tried to remove the md= stuff as well:
(raid=autodetect)
-----
md: Autodetecting RAID arrays.
md: Scanned 4 and added 4 devices.
md: autorun ...
md: considering sdc2 ...
md: adding sdc2 ...
md: sdc1 has different UUID to sdc2
md: adding sdb2
md: sdb1 has different UUID to sdc2
md: created md1
md: bind<sdb2>
md: bind<sdc2>
md: running: <sdc2><sdb2>
raid1: raid set md1 active with 2 out of 2 mirrors
md: considering sdc1 ...
md: adding sdc1 ...
md: adding sdb1 ...
md: created md0
md: bind<sdb1>
md: bind<sdc1>
md: running: <sdc1><sdb1>
raid1: raid set md0 active with 2 out of 2 mirrors
md: ... autorun DONE.
md0: unknown partition table
-----
Boot fails with the same mdadm error as the previous attempt.
This is all on 2.6.29. Seems to me like it is actually sort of working in
at least the last go. Or at least the raids are detected, but there is no
mention of the four partitions on one of them so perhaps it is not
detected properly? Have I made some error when creating the raids that
causes the autodetect to not notice that one of the raids is partitioned?
Any other potential mistakes I might have made that would lead to
autodetect failing?
Regards,
/Fredrik Pettersson
On Wed, 10 Jun 2009, Fredrik Pettersson wrote:
Hi,
A couple of years ago I converted my system to run off a software raid 1
rather than from a single disk. On the dual 250GB disks I have set up two
partitions:
-----
Disk /dev/sdb: 250.0 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00000000
Device Boot Start End Blocks Id System
/dev/sdb1 * 1 1246 10008463+ fd Linux raid autodetect
/dev/sdb2 1247 30401 234187537+ fd Linux raid autodetect
-----
sdb1/sdc1 is a raid 1 called /dev/md0, sdb2/sdc2 is a partitionable raid 1
called /dev/md_d0, partitioned and used for usr, var & home.
Partitions are set up as follows:
-----
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/md0 9851232 236736 9114080 3% /
udev 10240 76 10164 1% /dev
/dev/md_d0p1 29529044 8936164 19092880 32% /usr
/dev/md_d0p2 19685916 10876740 7809176 59% /var
/dev/md_d0p3 9842852 3453940 5888912 37% /home
none 517192 0 517192 0% /dev/shm
-----
At the time when I set this up I found that the only way for me to get it to
boot properly was to have the following kernel options in my grub.conf:
raid=noautodetect md=0,/dev/sdb1,/dev/sdc1 md=d0,/dev/sdb2,/dev/sdc2
As it was some time ago I don't recall exactly why that had to be there, but
it doesn't work without having those kernel options. I've just started
thinking of adding more software raid disks to my system and figured it would
be nice if autodetect would work for me so I would prefer to get rid of those
options. If I remove the "raid=noautodetect" bit, or all of it, then the
system fails to boot properly. From what I can see on the console it appears
to find the md_d0 raid and partitions just fine, but not the /dev/md0 raid
which obviously causes the boot to fail. So my question now is, why is
autodetect not working properly and what can I do to fix it?
I'm sure there is more information I should have provided here, please ask if
anything is missing. Here is my /proc/mdstat and the full entry from
grub.conf:
-----
# cat /proc/mdstat
Personalities : [raid0] [raid1] [raid6] [raid5] [raid4]
md_d0 : active raid1 sdc2[1] sdb2[0]
234187456 blocks [2/2] [UU]
md0 : active raid1 sdc1[1] sdb1[0]
10008384 blocks [2/2] [UU]
unused devices: <none>
-----
-----
title=Gentoo Linux 2.6.29-gentoo-r5
kernel (hd0,0)/boot/kernel-2.6.29-gentoo-r5 root=/dev/md0
raid=noautodetect md=0,/dev/sdb1,/dev/sdc1 md=d0,/dev/sdb2,/dev/sdc2
savedefault fallback
-----
Best regards, and thanks in advance for any answers.
/Fredrik Pettersson
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
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@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
