Justin Clacherty wrote:> Hi,
>
> I have set up a 40GB iscsi target on my san and when I add it in to
> the storage pool and it shows up as 40GB. When I try to create a 40GB
> volume in the ovirt UI it tries to but fails. The error message is
> that the volume will not fit. If I create one smaller than 40GB it
> works. Is anyone else experiencing this?
>
> Also, if I then start a virtual machine up to install on the newly
> created volume it sees both the smaller (39GB in this case) partition
> and a 40GB partition (presumably the failed one).
>
> Cheers,
> Justin.
>
Hi Justin,
Ian may be able to provide a more complete answer, but there are a
couple things that are probably going on with the 39GB vs. 40GB size.
First of all, if you've got a 40GB iSCSI LUN and you want to create an
oVirt storage volume under it, we're creating a Volume Group on the LUN
and creating Logical Volumes as storage volumes via libvirt, so the size
available for a single LVM volume on the lun will be slightly smaller
due to the LVM overhead.
The second issue is that while libvirt (and the oVirt DB) deal with
storage sizes internally in KB, we're using GB in the UI at the moment
and converting on the back end. This means for now you can only deal
with an integral number of gigabytes. We need to do some re-thinking on
how we handle storage and memory units -- in the above case you may have
been able to create a 39.6GB volume (or some other value between 39 and
40 GB). If you really want to use the whole 40GB lun for a single VM
you don't need to create an LVM volume -- just use the iscsi lun (shown
in the UI as an iscsi storage volume).
As for why you see both in your VM I haven't seen that, so I'm not sure
what would cause that -- Ian do you have any ideas on this point?
Scott