Alex Schuster <wo...@wonkology.org> wrote: > cov...@ccs.covici.com writes: > > > I have a question -- where would lvm put a snapshot and how could I > > pass some list of excludes to rdiff-backup. I have an lvm which is > > taking all the PEs and a snapshot would take up lots of disk space -- > > or would it. Would I need some free pes to put the snapshot? > > An LVM snapshot has to be in the same volume group as the LVM. If all your > physical extends are full, this will not work I'm afraid. > But you can reduce the size of one LVM with lvreduce. Of course you have > to resize the file system inside first. This is a little more complicated > than extending the size, because you have to specify the size when > reducing the file system and the LVM. And the file system has to be > unmounted :( > > Let's say you want to reduce your data partition of 15G to 10G: > > umount /dev/myvg/data > fsck -f /dev/myvg/data > resize2fs /dev/myvg/data 9G > lvresize -L 10G /dev/myvg/data > resize2fs /dev/myvg/data > mount /dev/myvg/data > > The 2nd resize2fs maximizes the size of the fs inside the LVM. I do not > know (does anyone else?) if you could skip this and reduce it to 10G in > the first resize2fs step. Just to be on the safe side I reduce it a little > more, and let it adapt do the reduced LVM size afterwards. > > The snapshot itself takes nearly no space at all - it only keeps the > changes that occur in the LVM while the snapshot is in place. So it grows > when you modify the LVM you snapshotted. When you do not much > modifications, 15-20% is enough according to the lvcreate man page. And I > think I had it much lower without problems. I would expect that it can be > really small when you do not change the original LVm much. snackup uses 2G > as default, change this with option -s. Of course, when you do large > modifications, like creating larger files, this may be too small. > > Excludes can be given with the -x option (multiple times). And have a look > at the config template that snackup -T gives you. Near the bottom, the > variable oXclude is defined. It is an array, just change it to your needs. > it already excludes things like ccache, kdecache-* directories, > */tmp/portage, and the dreaded nepomuk directory fo KDE4 because this > sometimes gets really REALLY large here. > > snackup -x dip -x dap would exclude the stuff already pre-defined and dip > and dap. If you want to exclude dip and dap only, call snackup -x "" -x > dip -x dap. But I find it easier to adapt the oXclude array.
Thanks, very interesting and I will have a look. -- Your life is like a penny. You're going to lose it. The question is: How do you spend it? John Covici cov...@ccs.covici.com