You were using skip/seek wrong. This is just pseudo code? I use bash or ksh, you can't do "n=n+1". You don't ever end, again pseudo code I assume. I would only do this if the filesystem on md0 is not mounted. Guy n=0 while dd if=/dev/md0 of=/tmp/block count=x_for_efficiency skip=n dd of=/dev/md0 if=/tmp/block count=x_for_efficiency seek=n n=n+1 loop -----Original Message----- From: linux-raid-owner@xxxxxxxxxxxxxxx [mailto:linux-raid-owner@xxxxxxxxxxxxxxx] On Behalf Of David Greaves Sent: Thursday, August 12, 2004 8:31 AM To: Guy Cc: 'Gordon Henderson'; 'Philip Molter'; linux-raid@xxxxxxxxxxxxxxx Subject: Re: Force parity resync on raid5? 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... > >Good luck! >- >To unsubscribe from this list: send the line "unsubscribe linux-raid" in >the body of a message to majordomo@xxxxxxxxxxxxxxx >More majordomo info at http://vger.kernel.org/majordomo-info.html > >- >To unsubscribe from this list: send the line "unsubscribe linux-raid" in >the body of a message to majordomo@xxxxxxxxxxxxxxx >More majordomo info at http://vger.kernel.org/majordomo-info.html > > > - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
