Moving/merging a filesystem back into /
kmk at sanitarium.net
Mon Dec 2 13:17:06 MST 2013
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First, make sure you have good backups in case anything goes wrong.
Second, make sure your root (which appears to be a regular partition
rather than an lvm2 slice) is large enough to handle your current /usr
Third, consider whether you should be moving root into lvm2 rather
than moving /usr out of it as this would increase flexibility in the
future rather than reducing it.
> -a, or -axAHX, or -apogXx, or -PvasHAX
> or should I go with a combined -apogsvxAHPX ?
- -aH is enough for most things. If your current /usr is mounted with
the acl option then you should use -A. If you have USE=caps or
caps-ng then you will need -X. -v, -i, and -P are modifications to
the output of rsync and purely up to you. Most of the rest of that is
included in -a. -S might save you a little space but never use it on
/boot (I know you said /usr but I felt like saying that anyway).
> 1. Boot off of the latest gentoo LiveDVD
I would use SystemRescueCD. It is Gentoo based but much better setup
for this kind of work. It is also nice to have around.
> 2. Mount /
> mount /dev/sda3 /mnt/gentoo/
You might have to specify more options here. Check what they are
before you shut down.
> There should already be a /usr directory where it was being
> mounted before, right? If not, then I guess I create it with
> root:root 755 permissions.
> 3. Mount old /usr to be moved/merged
> vgscan vgchange -a y mount /dev/vg/usr /mnt/gentoo/oldusr
I think SystemRescueCD will do part of that for you but if not those
are the right steps (not including the mkdir)
> 4. Copy /oldusr to /usr
> rsync -a? /mnt/gentoo/oldusr/ /mnt/gentoo/usr/ Are the trailing
> slashes required/important/necessary?
> Which arguments should I use?
> 5. Edit /etc/fstab and comment/remove the /usr line
> nano -wc /mnt/gentoo/etc/fstab
> #/dev/vg/usr /usr reiserfs noatime 0 0
Change this to mount in /olduser. You have no reason to delete it at
this point so you can keep it around just in case. At least until you
need to reclaim the vg space.
> 6. Unmount mounted filesystems
> umount /mnt/gentoo/oldusr umount /mnt/gentoo
> 7. Reboot into new system
While you are at it I would recommend converting from reiserfs to
ext4. Reiserfs has never really been all that reliable and ext4
caught up to it and passed it on performance for most things.
> Best regards,
Kevin Korb Phone: (407) 252-6853
Systems Administrator Internet:
FutureQuest, Inc. Kevin at FutureQuest.net (work)
Orlando, Florida kmk at sanitarium.net (personal)
Web page: http://www.sanitarium.net/
PGP public key available on web site.
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