Hi Marek,
On 13/10/15 16:04, Marek wrote:
Could it be that the raid wasnt synced at the time i overwrote
/dev/sda ? i have run the command you suggested and will report after
its done. would it still be possible to recover the raid?
So what likely happened is that you wrote ontop of a RAID member drive
while the RAID was likely not assembled (during your install).
If you do a resync it won't unfortunately *recover* the previously
written data, it will go over each stripe and recalculate the parity. It
is true that it *might* have been possible to do the opposite operation
by not touching anything and figuring out the previous data with the
data and parity blocks from the remaining RAID members (assuming they
weren't overwritten), but it would have been a tricky operation.
However, since you've done the resync now, the previous parity blocks
have been overwritten leaving you with a consistent RAID, but with part
of the data on a disk that you want to revert.
At this stage you should recover the old data from a backup.
On Tue, Oct 13, 2015 at 4:36 PM, Weedy <weedy2887@xxxxxxxxx> wrote:
On 13 Oct 2015 10:06 am, "Marek" <mlf.conv@xxxxxxxxx> wrote:
no, i had a working raid consisting of 4 2TB drives (raid5)
sda,sdb,sdc,sdb ( no partitions were created on drives) - then i
accidentally deleted /dev/sda by installing ubuntu. when inspecting
dev/md127 with a hex editor i discovered first 12mb are missing.
Wait, if it's a raid5 can't you just resync it?
Also I believe 1.2 metadata is at the end of a partition. If your saying the
raids hasn't noticed you can run a check and it should fix itself.
echo check > /sys/block/mdX/md/sync_action
--
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
