what about n=0 while dd if=/dev/md0 of=/tmp/block count=x_for_efficiency seek=n dd of=/dev/md0 if=/tmp/block count=x_for_efficiency seek=n n=n+1 loop
?
This would read the good data and force a rewrite - would you need to stop any optimisers?
David
Guy wrote:
Ouch! No!!
This would re-build data from parity!!! He thinks his parity is bad. He wants to re-build the parity from the data! I don't know if this can even be done! Recovering from a power failure does force a re-build (2.4), but from what I remember the system looks like it is re-building a failed disk, which is not what he wants to do. If the parity was good, re-building any 1 disk would be fine.
Guy
-----Original Message----- From: linux-raid-owner@xxxxxxxxxxxxxxx [mailto:linux-raid-owner@xxxxxxxxxxxxxxx] On Behalf Of Gordon Henderson Sent: Tuesday, August 10, 2004 5:04 AM To: Philip Molter Cc: linux-raid@xxxxxxxxxxxxxxx Subject: Re: Force parity resync on raid5?
On Mon, 9 Aug 2004, Philip Molter wrote:
How do I force a parity resync on a raid5 array? Under 2.4, I would do
this by hard cycling the box and when it came back up, it would
automatically resync the array. Under 2.6, this appears to have gone
away.
I don't know about 2.6, (still living with 2.4) but can't you simply do:
raidhotremove /dev/mdX /dev/hdYZ
followed by
raidhotadd /dev/mdX /dev/hdYZ
or /dev/sdYZ if SCSI disks...
However, picking the right disk to remove might be tricky... And if you were at all unsure about data on the disks, maybe rebooting and doing a hard fsck of the partition(s) in maintenance mode might be a good thing too...
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