[PVE-User] BTRFS...

Wolfgang Bumiller w.bumiller at proxmox.com
Wed Feb 3 08:07:29 CET 2016

> On February 2, 2016 at 8:07 PM Adam Thompson <athompso at athompso.net> wrote:
> On 16-02-02 11:24 AM, Gilberto Nunes wrote:
> > Hi
> >
> > And what if I work with BTRFS inside the VM???
> > The FS where VM image lay could be any other FS... Currently, I am use 
> > GlusterFS + XFS.
> > I need LVM or BRTFS inside the VM, in order to resize disk partition...
> > And I am between LVM or BRTFS....
> Only if you need to do *online* resizes (without unmounting the 
> filesystem).  If you can live with unmounting the filesystem, plain old 
> ext3 (and ext4) can do what you need.  Of course, if it's the root 
> filesystem you need to resize, the only way to unmount it is to shut 
> down the VM and reboot it in single-user mode.  I think you might need 
> to boot off a CD to resize the root fs, can't remember if there's a way 
> around it.

Actually resize2fs works on mounted file systems as long as you're only
growing it and not shrinking it, including the root filesystem.


> On February 2, 2016 at 4:38 PM Gilberto Nunes <gilberto.nunes32 at gmail.com> wrote:
> That's other doubt... I will lose data if I do it with parted resizepart???

No, but naturally you should make a backup just in case, especially when
you do this the first time.
Of course there are some limitations when you need online resizing without
downtime. Then you can only grow a partition without moving it. In other
words you can only resize a partition if there's physical free space directly
after it. (Most of the time this is the case since you usually have the
boot partition first and then the root and maybe a home or data partition,
and most of the time that last one is the one you want to resize ;-) )
Eg. with [boot, root, home] after resizing the physical disk you end up with
[boot, root, home, <frees space>], so you can only resize the home partition.
If you can afford down time you can also use parted to move partitions so that
you can resize any of them.  This however takes a lot longer and is a bit
more risky, so in this case you should _always_ make a backup even if you know
what you're doing.

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