Re: raid 5 created with 7 out of 8

Hi, I dont know whats up with the "VERS = 9000" output, but its
definitively from mdadm, as it's been present at every attempt at
creating the array.

However, I've upgraded to the 2.4.28 kernel and that made no
difference, but issuing mdadm -Cf /dev/md0 -l5 -n8 -c256 /dev/hd[e-l]1
(note the "f" made all my problems go away, the array is now fully
operational)

And for the stripe size, thats just an performance experiment, seems
like 256 was the winner in the end though. I can try to recreate the
problem later today if the output of mdadm -D /dev/md0 is of any
interest in finding out if this is a bug or just me. (It should also
be mentioned that the older version of mdadm that shipped with
slackware 10 also produced the same problem)

-Bjorn

On Sun, 9 Jan 2005 22:24:27 -0500, Guy [off-list ref] wrote:

From 1.8.1:
This is a "development" release of mdadm.  It should *not* be
considered stable and should be used primarily for testing.
The current "stable" version is 1.8.0.

Your email shows "VERS = 9000".  Was that a command line option?  Or output
from mdadm?

The only other odd thing I see...  You have the largest chunk size I have
seen (-c512).  But I don't know of any limits.

I did create an array with this command line.  No problems.
mdadm -C /dev/md3 -l5 -n8 -c512 /dev/ram[0-7]

from cat /proc/mdstat:
md3 : active raid5 [dev 01:07][7] [dev 01:06][6] [dev 01:05][5] [dev
01:04][4] [dev 01:03][3] [dev 01:02][2] [dev 01:01][1] [dev 01:00][0]
     25088 blocks level 5, 512k chunk, algorithm 2 [8/8] [UUUUUUUU]

Send output of:
mdadm -D /dev/md0

I am using mdadm V1.8.0 and kernel 2.4.28.

Guy

-----Original Message-----
From: linux-raid-owner@vger.kernel.org
[mailto:linux-raid-owner@vger.kernel.org] On Behalf Of Bjørn Eikeland
Sent: Sunday, January 09, 2005 8:39 PM
To: linux-raid@vger.kernel.org
Subject: raid 5 created with 7 out of 8

Hi, I'm trying to set up a raid5 array using 8 ide drives (
/dev/hd[e-l] ) but I'm having a hard time.

I'm using slackware 10, kernel 2.4.26 and madm 1.8.1 (downloading
2.4.28 overnight now)

The problem is mdadm creates the array with 7 of 8 drives up and
running and the last as a spare and does not start recovering with the
spare. And it will not let me remove it and re-add it. Below follows a
script output of the whole thing (less repartitioning the drives and
zero'ing any remaining superblocks)

Any help will be greatly appreciated.
-thanks

root@filebear:~# mdadm -C /dev/md0 -l5 -n8 -c512 /dev/hd[e-l]1
VERS = 9000
mdadm: array /dev/md0 started.
root@filebear:~# cat /proc/mdstat
Personalities : [linear] [raid0] [raid1] [raid5]
read_ahead 1024 sectors
md0 : active raid5 hdl1[8] hdk1[6] hdj1[5] hdi1[4] hdh1[3] hdg1[2]
hdf1[1] hde1[0]
     1094017792 blocks level 5, 512k chunk, algorithm 2 [8/7] [UUUUUUU_]

unused devices: <none>
root@filebear:~# mdadm /dev/md0 -f /dev/hdl1
mdadm: set /dev/hdl1 faulty in /dev/md0
root@filebear:~# mdadm /dev/md0 -r /dev/hdl
mdadm: hot removed /dev/hdl1
root@filebear:~# mdadm /dev/md0 -a /dev/hdl1
mdadm: hot add failed for /dev/hdl1: No space left on device
root@filebear:~# mdadm /dev/md0 -f /dev/hde1
mdadm: set /dev/hde1 faulty in /dev/md0
root@filebear:~# mdadm /dev/md0 -r /dev/hde1
mdadm: hot removed /dev/hde1
root@filebear:~# mdadm /dev/md0 -a /dev/hde1
mdadm: hot add failed for /dev/hde1: No space left on device
-
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