Re: (Re: Questions regarding startup of imsm container)

[Randy Terbush <randy@terbush.org>]

To follow-up this startup challenge... here is what I am getting.

mdraid is being started with mdadm -As

I have the following in mdadm.conf

HOMEHOST Volume0
#DEVICE /dev/sd[bcde]
AUTO +imsm hifi:0 -all
ARRAY metadata=imsm UUID=30223250:76fd248b:50280919:0836b7f0
ARRAY /dev/md/Volume0 container=30223250:76fd248b:50280919:0836b7f0
member=0 UUID=8a4ae452:da1e7832:70ecf895:eb58229c

The following devices are being created.

# ls -l /dev/md/
total 0
lrwxrwxrwx 1 root root 6 Mar 23 08:10 0 -> ../md0
lrwxrwxrwx 1 root root 8 Mar 23 08:17 126 -> ../md126
lrwxrwxrwx 1 root root 8 Mar 23 08:17 127 -> ../md127
lrwxrwxrwx 1 root root 8 Mar 23 08:17 imsm0 -> ../md127
lrwxrwxrwx 1 root root 8 Mar 23 08:17 Volume0 -> ../md126

cat /proc/mdstat
Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4]
md126 : active raid5 sdb[3] sdc[2] sdd[1] sde[0]
      2930280448 blocks super external:/md127/0 level 5, 64k chunk,
algorithm 0 [4/4] [UUUU]
      [>....................]  resync =  1.8% (18285824/976760320)
finish=182.6min speed=87464K/sec

md127 : inactive sde[3](S) sdb[2](S) sdc[1](S) sdd[0](S)
      9028 blocks super external:imsm

unused devices: <none>

So the container device is getting moved from md0 to md127. Not sure why.

And would sure like to have a write-intent bitmap active to avoid this
resync issue which seems to be happening way too frequently.


On Tue, Mar 23, 2010 at 6:58 AM, Randy Terbush <randy@terbush.org> wrote:
> On Tue, Mar 23, 2010 at 2:04 AM, Luca Berra <bluca@comedia.it> wrote:
>>> # mdadm --version
>>> mdadm - v3.1.2 - 10th March 2010
>>>
>>> # mdadm -Es
>>> ARRAY metadata=imsm UUID=30223250:76fd248b:50280919:0836b7f0
>>> ARRAY /dev/md/Volume0 container=30223250:76fd248b:50280919:0836b7f0
>>> member=0 UUID=8a4ae452:da1e7832:70ecf895:eb58229c
>>>
>>> # ls -l /dev/md/
>>> total 0
>>> lrwxrwxrwx 1 root root 6 Mar 22 20:54 0 -> ../md0
>>> lrwxrwxrwx 1 root root 8 Mar 22 20:54 127 -> ../md127
>>> lrwxrwxrwx 1 root root 8 Mar 22 20:54 Volume0_0 -> ../md127
>>>
>>> As you can see, the name for the link in /dev/md does not agree with
>>> the name that the Examine is coming up with.
>>
>> please read mdadm.conf manpage, under the section "HOMEHOST"
>
> If I understand this correctly, I think there still may be a problem
> as I am not clear on how I could have set the homehost in the metadata
> for this imsm array. The Volume0 is provided by imsm and is configured
> in the option ROM.
>
> The underlying question here is should the ARRAY entry in mdadm.conf
> be changed to reflect the on disk name of the device, or is the
> startup process munging that entry when it processes mdadm.conf to
> strip the _0.
>
> I'll try setting HOMEHOST <ignore> to see if I am getting expected results.
>
> I seem to have some problems with startup still as I have the
> following entry where the container is now md127. Was md0 when
> originally created.
>
> # cat /proc/mdstat
> Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4]
> md126 : active raid5 sdb[3] sdc[2] sdd[1] sde[0]
>      2930280448 blocks super external:/md127/0 level 5, 64k chunk,
> algorithm 0 [4/4] [UUUU]
>
> md127 : inactive sde[3](S) sdb[2](S) sdc[1](S) sdd[0](S)
>      9028 blocks super external:imsm
>
> unused devices: <none>
>
> I am also running into a problem where fsck will crash during boot on
> the ext4 filesystems that this array contains. No problem running fsck
> after the boot process has completed so have not seemed to find the
> magic with order of startup for this device.
>
>
>>
>>> Is it better to just forgo the ARRAY statements and go with an AUTO +imsm?
>>>
>
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