Andrew Reilly wrote: > [*] The production server is using a software RAID mirror on > a pair of SATA drives on a low-end Intel P4/ICH6 motherboard, > using ar(4), configured by atacontrol. Fsck on 6.x can't find > any superblocks on /usr, but 5.5 is fine.
It's a horrible hack, and you should definitely have good backups
before trying this and there's no guarantee it will even work, but...
tunefs -A {mumble} /dev/ad0s1a
will re-write all of the superblocks on your disk partition. For
{mumble} I used '-n enable' (ie. turn on softupdates), which happened to
be a no-op on that system, but you could use practically anything tunefs
provides.
The problem I had was sort of going in the other direction though: I'd
booted fixit mode from a 6.1 Install disk in order to transfer the
contents of a failing 4.x system disk to a new drive, and while I could
slice, partition and create UFS1 filesystems perfectly happily under 6.1
and use 6.1 dump and restore to copy the disk contents, on reboot 4.x
couldn't read the superblocks properly, so the system wouldn't fsck
properly and get past single user mode. The trick of using 'tunefs -A'
fixed that, and the machine is now running 4.11-RELEASE-p25 perfectly
happily on the replacement hard drive.
Cheers,
Matthew
--
Dr Matthew J Seaman MA, D.Phil. 7 Priory Courtyard
Flat 3
PGP: http://www.infracaninophile.co.uk/pgpkey Ramsgate
Kent, CT11 9PW
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