[CentOS] CentOS 7 - xfs shrink & expand

Wed May 13 17:45:38 UTC 2020
Jason Edgecombe <jwedgeco at uncc.edu>

Hi,

XFS filesystems cannot be shrunk. If you need to shrink an XFS file system,
then you have to backup the data, delete the entire filesystem, resize the
volume in LVM, then create a new filesystem and restore the data from
backup.

Ref:
https://xfs.org/index.php/XFS_FAQ#Q:_Is_there_a_way_to_make_a_XFS_filesystem_larger_or_smaller.3F

Jason
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On Wed, May 13, 2020 at 1:05 PM Frank M. Ramaekers Jr. <frank at ramaekers.com>
wrote:

> I'll try that...I was using instructions I found on the internet for
> single-user/maintenance mode.   From the grub screen you enter 'e' and
> modify the linux16 line...etc.
>
> Okay, I'll try that next.
>
> Thanks Simon!
>
> On 5/13/2020 7:28 AM, Simon Matter via CentOS wrote:
> > Hi,
> >
> >> Yeah, I tried that but ran into a problem.  It came up fine in
> >> single-user/maintenance mode.   The mount command shows all of the
> >> mounted file systems, but after I 'chroot /sysroot', the mount failed
> >> (with some problem with mtab, sorry don't have the exact error
> >> message).  So I couldn't mount my 32TB RAID (where the xfsdump file
> was).
> > I think you misunderstood what I meant. You appear to have booted into
> > rescue mode, but that's not what I meant. What I meant is good old single
> > user mode. The state you'll get with "telinit 1" or with "s" or "1" as a
> > kernel boot option.
> >
> > For what you want to do not a single reboot is required.
> >
> > Regards,
> > Simon
> >
> >> On 5/13/2020 12:48 AM, Simon Matter via CentOS wrote:
> >>> Hi,
> >>>
> >>>> I'm having some difficulty finding a method to shrink my /home to
> >>>> expand
> >>>> my /.  They both correspond to LVMs.  It is my understanding that one
> >>>> cannot shrink a xfs filesystem.  One must back it up (xfsdump), remove
> >>>> (lvremove) redefine it and then restore it back (xfsrestore).
> >>>>
> >>>> Okay, I'm running into a problem where /home  needs to be "unused".
> If
> >>>> tried going in to "maintance mode", but I ran into a problem with the
> >>>> mount command (after issuing a 'chroot /sysroot').  I then tried using
> >>>> SystemRescueCD to boot to, but it wouldn't mount my 32TB RAID USB
> drive
> >>>> (something about too big).
> >>>>
> >>>> Any thoughts or suggestions?
> >>> What is the problem if you boot directly into maintenance mode? Then it
> >>> should be possible to backup home to a remote destination, unmount
> >>> /home,
> >>> remove the home LV, expand /, recreate home and mount it, restore from
> >>> backup and you're done. No need to use any SystemRescueCD or other
> tool.
> >>>
> >>> Regards,
> >>> Simon
> >>>
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