I need to add space to /var (thank you, libreoffice), which is on lvm.
Since my one volume group vg is getting low, I thought this would be a
good time to extend it as well.
Alan (McKinnon) has posted very helpful lvm bits (reprinted below).
Following alan's bottom up creation mandate I believe the idea is
phy disk: /dev/sda my only drive
phy part: fdisk create another partition of type LVM (/dev/sda8)
phy vol: pvcreate /dev/sda8
vol grp: vgextend vg /dev/sda8
log vol: lvextend --size +10G /dev/vg/var
file sys: resize2fs /dev/vg/var
files/dirs: not relevant
Questions
1. Apparently 2.6 (hence 3.x) kernels can expand mounted file systems
(/var is mounted as ext3).
Since I can't unmount /var because it is in use, I guess that, if I
every need to shrink /var, I would need to boot off a CD. Is that
correct?
Back in the day, we had single user mode for this, but I don't see
how to get the equivalent now.
Is it really safe to extend /var (i.e., /dev/vg/var) while mounted
as ext3? It sounds frightening since daemons could start running
and access /var.
2. Since currently /var is entirely from /dev/sda7 (my original lvm
partition) should I use the optional parameter to lvextend to
force the new space for /var to come from there as well?
lv extend --size +10G /dev/sda7
thanks in advance
allan
==================== from Alan McKinnon ==============================
Let's look first at the layers of stuff involved:
files & directories
file system
logical volume (LV)
volume group (VG)
physical volume (PV)
physical partition (i.e. /dev/sda1 etc)
physical disk (i.e. something Seagate etc made)
OK, there's a lot of stuff there. When you made the LV, you worked from
the bottom up
Nothing in that list can be bigger than the thing below it.
