gmirror and resizing partitions..

Reid Linnemann lreid at
Mon Jun 9 16:08:36 UTC 2008

Written by B. Cook on 06/09/08 10:23>>
> Hello all,
> I have a FreeBSD 7 machine that I am running gmirror on (ad4 and ad6).
> there is an /exports and /home that need to be resized.
> (right now they each are about 55G and /home needed to have been 100G
> and exports 10G)
> what do I need to do to fix this.
> I am assuming break the mirror, fdisk the /exports and /home then remake
> them, and then rebuild the mirror..
> right?
> What do I need to do with as little impact on the running server as
> possible.. as many services are already configured on this box and it's
> running :P
> (of course.. )
> Thanks in advance,
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What I would do is break the mirror, then resize the partitions and
newfs them on one disk. Then dump|restore the data from the other disk
to your new partitions, and recreate the mirror with the newly resized
disk and insert the other disk into that mirror. That disk should then
rebuild with the new partitioning.

Of course, you can only do this while the mirror is unused. So you're
going to have to have some degree of downtime on those filesystems. You
can minimize the downtime by killing the mirror and remounting the
filesystems direct from one disk while you work on repartitioning the
other. You may want to mount read-only, however, as the dump|restore may
take a significant amount of time and you wouldn't want to lose any data
that may be written to the other disk while you're busy copying from it.
When you've built the new mirror with the repartitioned disk and
dump|restored to it (don't forget the -L option on dump), remount the
partitions from the new mirror and then insert the second disk.

That's what I'd do, anyhow.

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