Re: [ext2resize] ext2online

[Andreas D. <ad...@tu...>]

On Oct 17, 2001  16:02 +0200, Jan Hanstede wrote:
> I have the following hd configuration:
> 
> Filesystem            Size  Used Avail Use% Mounted on
> /dev/hda1             888M  808M   34M  96% /
> /dev/hda2             251M   31k  237M   1% /tmp
> /dev/hda4             2.7G  1.4G  1.2G  52% /var
> 
> I would like to increase the hd space on hda1 by eating some free space of
> hda4. I want to use ext2online for this purpose. (cause hda1 must stay
> mounted). However it don't seem to work. I thought I had to shrink hda4
> first and then grow hda1 with this new free space. But I don't seem to be
> able/allowed to shrink hda4. How can I solve this?

You need to use something like GNU parted.  ext2resize and ext2online only
are able to resize the end of the filesystem, and do not do anything with
the partition table.  GNU parted uses mostly the same code to resize the
ext2 filesystem, but it also allows you to move the entire filesystems
around and change the partitioning.

Another option would be to remove the /tmp filesystem (delete /dev/hda2)
and grow /dev/hda1 into this free space.  You can also use ext2resize
to shrink /var by 260MB+, then shrink /dev/hda4 by some smaller amount
and create a new partition at the end of the disk in this new space.
You need to reboot at that point to get the kernel to recognize the new
partition table, and finally, you grow / to fill the new space at the
end of /dev/hda1, and create a new /tmp filesystem in the space at the
end of the disk.  You will also need to grow /var again to use up the
space at the end of /dev/hda4.

If you decide to use parted, you cannot do any of this while the
filesystem is mounted.  However, that isn't a big deal because you need
a reboot anyways because the kernel isn't very good at handling partition
table changes when any partition of that disk is in use.

> By the way I didn't apply any kernel patches cause I didn't see any
> reference in the docs/faqs (I just installed some redhat rpms). I asume you
> don't need any unless you have an older version 2.2 or something? (I use >
> 2.4)?

You need to have kernel patches for any online resizing.  There are
patches for 2.4 kernels in the "patches/" directory.  I have added this
to the docs for installing ext2resize.

Note that ext2online is mosly useful when you have LVM - you can grow
the "partition" without needing a reboot, and LVM "partitions" do not
need to be contiguous on disk, so it is easy to add space to filesystems
while they are mounted.

Cheers, Andreas
--
Andreas Dilger  \ "If a man ate a pound of pasta and a pound of antipasto,
                 \  would they cancel out, leaving him still hungry?"
http://www-mddsp.enel.ucalgary.ca/People/adilger/               -- Dogbert