On 10/10/2017 09:20 PM, Robert Nichols wrote:
For you, there really is no way around the messy and delicate process
of shrinking and relocating a filesystem and the LVM volumes to make
space for a larger /boot partition. Frankly, I would hesitate to do
that in place on my own system, and I have quite a bit of experience
with doing unspeakable things with LVM volumes. You really need to do
that resizing in the context of moving everything to another disk.
Agreed. If / and /home are on xfs you can't shrink anyway. I'm not
sure if ext4 can be shrunk while mounted (I seem to remember that it can't).
If it's a server that you don't want to take down for the time it
takes for that procedure, you can do amazing things with pvmove while
your system continues to run, but you still need another disk to hold
those volumes temporarily.
As long as there is enough slack space in the volume group you can do
this. If there is no slack space you have real problems, especially
with XFS (one reason I still use ext4 for many things, and one reason I
never fill the volume group to 100%).
I have done the pvmove and filesystem resize dance before, live, with
the second hard disk attached via iSCSI. The least fun piece is then
resizing the /boot partition and its filesystem. But I had enough slack
space in the volume group. What can be done here is unmounting /home,
shrinking /home the appropriate amount, and then you have enough slack
space to do the shrink and move (not fully live, but semi-live, and you
can't have any logged-in users with open files in /home). Shrinking
from the end of the filesystem and pv is easy; shrinking from the
beginning is hard and prone to errors. (gparted and similar do the move
of the end of a partition fine; moving the start is much much harder).
However, if you can shrink enough from the end you can put /boot on the
last partition on the disk instead of the first, although you will have
to do some grub stanza editing to get rid of /dev/sda1 and replace with
the appropriate device for the new /boot. So you could shrink /home,
shrink the pv, shrink the partition holding the pv (this is the risky
part), then add a partition to the end of the disk for the new /boot.
If you've never done this sort of thing before you may want to get
someone who has done this sort of thing to do it.
Otherwise, if you feel at all uncomfortable doing this it may just be
easier to pull a backup and reinstall.
_______________________________________________
CentOS mailing list
CentOS@xxxxxxxxxx
https://lists.centos.org/mailman/listinfo/centos
