On April 19, splee@plexio.com wrote:
> Hi,
>
> Is there a Howto for mdadm newbies? The Software raid Howto is too old
I don't know of any.
> to reference mdadm. I have some questions on how to proceed:
>
> 1. Do I need to mark my raid1 partitions with the type fd?
Only if you want to use autodetect. I don't.
> 2. I tried:
> mdadm -C /dev/md0 --level raid1 --raid-disks 2 /dev/hda1 missing
> and got the message:
> md: can not import hda1, has active inodes!
> md: error, md_import_device() returned -16
> Does this mean that the partitions to be added to /dev/md0 must be
> unmounted?
Yes, definately. Once a partition has beein included into an md
array, md *must* be the only thing accessing that partition, otherwise
confusion can result.
> 3. If #2 is yes then how do I convert my partitions to raid1? In using
> raidtools, I simply copied the live drive contents to a spare drive
> with "fd" type partitions and followed the instructions in the
> Boot+Root+Raid+LILO Howto.
Support /dev/hda1 was your live boot drive, and /dev/hdc1 was second
partition that you eventually wanted to raid1 together with /dev/hda1.
Then
1/ create a degraded raid1 using /dev/hdc1 only:
mdadm -C /dev/md0 --level raid1 --raid-disks 2 missing /dev/hdc1
2/ create a filesystem on /dev/md0 and mount it:
mkfs /dev/md0
mount /dev/md0 /mnt
3/ copy everything from / to /mnt
cp -ax / /mnt
could do it.
4/ modify /mnt/etc/fstab to think that / is on /dev/md0
5/ reboot with a kernel-parameter of:
md=0,/dev/hdc1 root=/dev/md0
6/ If this all seems to work properly, then add /dev/hda1 to the
raid1 array:
mdadm /dev/md0 -a /dev/hda1
and change the kernel-paramter line to
md=0,/dev/hda1,/dev/hdc1 root=/dev/md0
> 4. Is it possible to boot root raid1 with mdadm and no autodetect?
See above.
NeilBrown
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