On Mon, Jan 30, 2006 at 12:40:01PM -0700, Sebastian Kuzminsky wrote:
> Looks like Ext3 supports online grow, but only up to +16 GB, which
> makes it useless on modern disks, much less arrays of modern disks....
> Looks like offline grow & shrink are unlimited, which is good. Lots of
> old (unmaintained?) tools and kernel patches here, but lots of recent
> activity too. What's the current status?
Andreas Dilger's out-of-tree implementation of ext2/ext3 online resize
allowed one to run ext2prepare in order to prepare the filesystem for much
larger resizes. [The code can be found here: ext2resize.sf.net.]
The ext2prepare(8) man page says:
The ext2prepare command modifies an unmounted ext2 filesystem
on device so that ext2online(8) program can later resize the
mounted filesystem to be at least as large as size although the
actual maximum size will be some larger multiple of various
filesystem parameters. While ext2prepare must be run on
an unmounted filesystem, device does not have to currently be
as large as size. This allows one to later increase the
size of device and do the resize while the filesystem is mounted.
On the way toward kernel inclusion, a number of things changed, and some
changes were made to e2fsprogs for compatibility.
The e2fsprogs-1.38 mke2fs(8) man page on Fedora Core 4, under the OPTIONS section,
says:
resize=max-online-resize
Reserve enough space so that the block group descriptor table can
grow to support a filesystem that has max-online-resize blocks.
You can easily test it with a huge sparse file, i.e.,
dd if=/dev/zero of=/tmp/image.bin bs=4K seek=500000000 count=1 # ~2TB
mkdir /tmp/mnt
losetup /dev/loop0 /tmp/image.bin
mke2fs -b 4096 -j -E resize=2147483648 /dev/loop0 134217728 # 512GB, resize 8TB.
mount /dev/loop0 /tmp/mnt
df /tmp/mnt
ext2online /tmp/mnt
df /tmp/mnt
Make sure that you have 20GB or so of space on partition where you
create the image.bin.
Regards,
Bill Rugolsky
_______________________________________________
linux-lvm mailing list
linux-lvm@redhat.com
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
