12:26 p.m.
Hi all,
Does anyone have a working example of creation of a logical storage pool
and volume?
I'm hitting a wall getting logical volumes to work on RHEL 6 beta.
There's a single drive I'm trying to setup (sdc) as a libvirt managed
logical storage pool, but all volume creation on it fails.
Here's what I'm finding so far:
Prior to any storage pool work, only the host boot drive (sda) is in lvm.
# vgs
VG #PV #LV #SN Attr VSize VFree
vg_host2 1 3 0 wz--n- 465.27g 0
# pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 vg_host2 lvm2 a- 465.27g 0
# ls -la /dev/mapper
total 0
drwxr-xr-x. 2 root root 120 Jun 1 03:12 .
drwxrwxrwt. 21 root root 3920 Jun 1 03:12 ..
crw-rw----. 1 root root 10, 58 May 31 14:08 control
lrwxrwxrwx. 1 root root 7 May 31 14:10 vg_host2-lv_home -> ../dm-7
lrwxrwxrwx. 1 root root 7 May 31 14:08 vg_host2-lv_root -> ../dm-0
lrwxrwxrwx. 1 root root 7 May 31 14:10 vg_host2-lv_swap -> ../dm-8
#
Creation of a logical storage pool, using sdc:
# virsh pool-define-as guest_images_lvm logical - - /dev/sdc
libvirt_lvm /dev/mapper
Pool guest_images_lvm defined
# virsh pool-info guest_images_lvm
Name: guest_images_lvm
UUID: 17398035-8000-7252-ab25-58db95aed130
State: inactive
# virsh pool-build guest_images_lvm
Pool guest_images_lvm built
#
The physical device and volume group are seen in lvm:
# pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 vg_host2 lvm2 a- 465.27g 0
/dev/sdc libvirt_lvm lvm2 a- 465.76g 465.76g
# vgs
VG #PV #LV #SN Attr VSize VFree
libvirt_lvm 1 0 0 wz--n- 465.76g 465.76g
vg_host2 1 3 0 wz--n- 465.27g 0
#
Starting the logical pool works:
# virsh pool-start guest_images_lvm
Pool guest_images_lvm started
#
Creation of volumes fail:
# virsh vol-create-as guest_images_lvm volume1 8G
error: Failed to create vol volume1
error: internal error '/sbin/lvcreate --name volume1 -L 8388608K
/dev/mapper' exited with non-zero status 3 and signal 0: Volume group
name expected (no slash)
Run `lvcreate --help' for more information.
#
So, it looked like "/dev/mapper" in the pool-define-as command should
have instead been the LVM volume group again. That doesn't work either
though:
# virsh pool-define-as guest_images_lvm logical - - /dev/sdc
libvirt_lvm libvirt_lvm
Pool guest_images_lvm defined
# virsh pool-build guest_images_lvm
Pool guest_images_lvm built
# virsh pool-start guest_images_lvm
Pool guest_images_lvm started
# virsh vol-create-as guest_images_lvm volume1 8G
error: Failed to create vol volume1
error: cannot read path 'libvirt_lvm/volume1': No such file or directory
Looking in the libvirtd logs for this last attempt, the volume was
actually successfully created. But libvirtd then checks for it's
presence (wrongly!), doesn't find it, and then lvremove's it:
03:01:24.000: debug : virRunWithHook:832 : /sbin/lvcreate --name
volume1 -L 8388608K libvirt_lvm
...
03:01:24.223: debug : virRunWithHook:848 : Command stdout: Logical
volume "volume1" created
...
03:01:24.223: error : virStorageBackendLogicalCreateVol:616 : cannot
read path 'libvirt_lvm/volume1': No such file or directory
...
03:01:24.223: debug : virRunWithHook:832 : /sbin/lvremove -f
libvirt_lvm/volume1
Guessing I'm either doing something wrong, or hitting bugs, or ?
Anyone have ideas/suggestions/etc?
Regards and best wishes,
Justin Clift
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