Michael Guntsche wrote:
On Mar 1, 2008, at 23:41, Michael Guntsche wrote:
mdadm -w /dev/md1 works if I call it after assembling.
If do not call it, mount the array and start writing to it, it
changes to "active"
but the rebuild process does not kick in.
The only way it works for me now is.
* Stop the array
* assemble it again with mdadm --assemble --scan
* Call mdadm -w /dev/md1
Good morning,
I found out why I am seeing this behaviour but I still do not know if
it is a bug or not.
The arrays are assembled in an initramfs. Debian's mdadm tool has a
script that assembles the arrays.
Now this script has the following entry.
# prevent writes/syncs so that resuming works (#415441). See
http:/bugs.debian.org/415441 for more information.
echo 1 > /sys/module/md_mod/parameters/start_ro
Changing this sysfs entry to 0, gives me the expected result if I do a
stop -> assemble with my 1.0 array.
It starts reysncing and everything is ok. According to the replies in
this bug, setting start_ro to 1 should NOT stop the automatic resync
after a write to it, but this seems to have changed now.
So, is this a change in behaviour or is it a bug. If it is the former,
I probably need to talk with the debian guys about it, if it is a bug
I wait for a fix and comment the entry in the mean time.
Note that if you don't start_ro I don't believe you will be able to use
the resume feature. The use of -w option would seem safer. I haven't
looked at the patch Neil submitted to start rebuild/reshape at the first
write, the logic seems correct to work with resume, nothing should start
until a user write.
--
Bill Davidsen <davidsen@xxxxxxx>
"Woe unto the statesman who makes war without a reason that will still
be valid when the war is over..." Otto von Bismark
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