[ovirt-users] Re: Unclear how to add local (POSIX) storage
On Thu, Feb 03, 2022 at 03:07:20PM +0200, Nir Soffer wrote:
On Thu, Feb 3, 2022 at 2:30 PM Richard W.M. Jones
<rjones(a)redhat.com> wrote:
>
>
> I'm following the instructions here:
>
https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.2/...
>
> I've also added an extra virtual disk to my host node which appears as
> /dev/sdb. Although the disk is partitioned, /dev/sdb1 is not created.
> Is udev broken in oVirt node?
>
> I cannot see anywhere in the dialog where you specify the name of the
> device (eg. "/dev/sdb1"). So how's it supposed to work?
>
> It doesn't work, giving an information-free error message:
>
> Error while executing action Add Storage Connection: Problem while trying to mount
target
You can find more info on the failure in:
/var/log/vdsm/supervdsmd.log
vdsm.storage.mount.MountError: Command ['/usr/bin/mount', '-t',
'xfs', '/srv', '/rhev/data-center/mnt/_srv'] failed with rc=32
out=b'' err=b'mount: /rhev/data-center/mnt/_srv: /srv is not a block
device.\n'
I suppose it expects the name of the block device (ie. /dev/sdb)
rather than the mount point there.
It also turns out the new device has been "captured" by multipathd:
# multipath -ll
0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-1 dm-0 QEMU,QEMU HARDDISK
size=100G features='1 queue_if_no_path' hwhandler='0' wp=rw
`-+- policy='service-time 0' prio=1 status=active
`- 0:0:0:1 sdb 8:16 active ready running
I've so far not found a way to disable multipathd effectively. Even
stopping and disabling the service and rebooting doesn't help so I
guess something starts it up.
Posix compliant is basically NFS without some mount options:
https://github.com/oVirt/vdsm/blob/878407297cb7dc892110ae5d6b0403ca972492...
Using a local device on a host is less tested path, I'm not QE is testing
this (Avihai, please correct me if you do).
If you have multiple hosts, this will break if the local device does not have
the same name on all hosts (so using /dev/sdb1 is very fragile). If you have
one host it can be fine.
Any reason to add a device to the vm, instead of using an NFS server?
I guess that your purpose is testing virt-v2v with oVirt, so you want to test
a common configuration; NFS is very common for oVirt users.
I don't have an NFS server to use for this.
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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