all,
I am having problems setting up RAID 1 using Fedora core 3. Here are
the steps that I have taken to date.
1) On the first SCSI drive, I installed a clean version of Linux, the
hard drive is partitioned as follows:
/dev/sda1 /boot 512 Mbytes
/dev/sda2 /cvsroot 20 GBytes
/dev/sda3 /archives 20 GBytes
/dev/sda4 (extended partition)
/dev/sda5 /home 10 GBytes
/dev/sda6 swap 2 GBytes
/dev/sda7 / 14 GBytes
2) Downloaded the souce code for 2.6.11-8 recompiled the kernel with
RAID support included in the kernel, not as modules.
3) Build the partions on the second SCSI drive to match the first.
4) Set the partition types of sd[ab]2, sd[ab]3, sd[ab]5, sd[ab]6 and
sd[ab]7 to 0xFD (Linux Software Raid Autodetect)
5) rebooted the host, on reboot I had three mirroed partitions:
/dev/md0 : /dev/sda2 and /dev/sdb2
/dev/md1 : /dev/sda3 and /dev/sdb3
/dev/md2 : /dev/sda5 and /dev/sdb5
Question 1 - why did swap and root fail to become part of the array?
6) using mdadm with the examine flag, I found that neither /dev/sd[ab]6
or
/dev/sd[ab]7 had raid superblocks on them. Attempting to build
arrays
using:
mdadm --create /dev/md3 --level=1 --raid-devices=2 /dev/sd[ab]6
failed (sort of expected since swap was mounted).
7) booted with a rescue disk, and did not mount any of my partitions,
and then executed the following commands:
mdadm --create /dev/md3 --level=1 --raid-devices=2 /dev/sd[ab]6
mdadm --create /dev/md4 --level=2 --raid-devices=2 /dev/sd[ab]7
both of these commands succeeded, and cat-ing /proc/mdstat showed
to raid arrays that were in the process of synching.
8) I let the two arrays finish synching, and then rebooted the computer
normally. I received a `ton' of messages about not being able to
touch various files in the root file system because the root file
system is read-only. After a while I finally did get a shell, and
I was able cat /proc/mdstat - I saw the expected five arrays,
however
the array for the root file system only had one drive in it:
....
md4 : active raid sdb7[1]
11759424 blocks [2/1] [_U]
....
All the other raid arrays had two entries (as expected) as were
readible
as well as writable.
On examining dmesg, I fould the following:
md: Autodetecting RAID arrays
md: could not bd_claim sda7
md: autorun...
md: considering sdb7...
md: adding sdb7...
so it seems that the RAID subsysem is not able to access / control
my root partition.
Question 2 - What do I need to do to be able to RAID my root
partition?
Question 3 - What do I need to do to fix my `read-only' file system
problems?
Questions 2 and 3 are probably related.
Note: I was able to execute the command:
mount / -o remount,rw
to make my root filesystem read-write.
9) Finally, I rebooted into rescue mode without mounting any of my
drives,
manually mounted /dev/sda7 and copied /etc/mdadm.conf to the floppy
and then unmounted /dev/sda7. Next I ran:
mdadm --assemble --scan --config=/mnt/floppy/mdadmconf
and all five of my RAID arrays came up, with two members each and
the
array holding my root file system was writable.
Any suggestiong on what I should try next.
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