<div dir="ltr"><div><div><div>Gary,<br><br></div>See this wiki page, it explains how to import storage domains :<br><a href="http://www.ovirt.org/develop/release-management/features/storage/importstoragedomain/">http://www.ovirt.org/develop/release-management/features/storage/importstoragedomain/</a><br><br></div>Regards,<br><br></div>Fred<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Feb 15, 2017 at 10:15 PM, Nir Soffer <span dir="ltr"><<a href="mailto:nsoffer@redhat.com" target="_blank">nsoffer@redhat.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="HOEnZb"><div class="h5">On Wed, Feb 15, 2017 at 9:30 PM, Gary Lloyd <<a href="mailto:g.lloyd@keele.ac.uk">g.lloyd@keele.ac.uk</a>> wrote:<br>
> Hi Nir thanks for the guidance<br>
><br>
> We started to use ovirt a good few years ago now (version 3.2).<br>
><br>
> At the time iscsi multipath wasn't supported, so we made our own<br>
> modifications to vdsm and this worked well with direct lun.<br>
> We decided to go with direct lun in case things didn't work out with OVirt<br>
> and in that case we would go back to using vanilla kvm / virt-manager.<br>
><br>
> At the time I don't believe that you could import iscsi data domains that<br>
> had already been configured into a different installation, so we replicated<br>
> each raw VM volume using the SAN to another server room for DR purposes.<br>
> We use Dell Equallogic and there is a documented limitation of 1024 iscsi<br>
> connections and 256 volume replications. This isn't a problem at the moment,<br>
> but the more VMs that we have the more conscious I am about us reaching<br>
> those limits (we have around 300 VMs at the moment and we have a vdsm hook<br>
> that closes off iscsi connections if a vm is migrated /powered off).<br>
><br>
> Moving to storage domains keeps the number of iscsi connections / replicated<br>
> volumes down and we won't need to make custom changes to vdsm when we<br>
> upgrade.<br>
> We can then use the SAN to replicate the storage domains to another data<br>
> centre and bring that online with a different install of OVirt (we will have<br>
> to use these arrays for at least the next 3 years).<br>
><br>
> I didn't realise that each storage domain contained the configuration<br>
> details/metadata for the VMs.<br>
> This to me is an extra win as we can recover VMs faster than we can now if<br>
> we have to move them to a different data centre in the event of a disaster.<br>
><br>
><br>
> Are there any maximum size / vm limits or recommendations for each storage<br>
> domain ?<br>
<br>
</div></div>The recommended limit in rhel 6 was 350 lvs per storage domain. We believe this<br>
limit is not correct for rhel 7 and recent ovirt versions. We are<br>
testing currently<br>
1000 lvs per storage domain, but we did not finish testing yet, so I cannot say<br>
what is the recommended limit yet.<br>
<br>
Preallocated disk has one lv, if you have thin disk, you have one lv<br>
per snapshot.<br>
<br>
There is no practical limit to the size of a storage domain.<br>
<span class=""><br>
> Does Ovirt support moving VM's between different storage domain type e.g.<br>
> ISCSI to gluster ?<br>
<br>
</span>Sure, you can move vm disks from any storage domain to any storage domain<br>
(except ceph).<br>
<div class="HOEnZb"><div class="h5"><br>
><br>
><br>
> Many Thanks<br>
><br>
> Gary Lloyd<br>
> ______________________________<wbr>__________________<br>
> I.T. Systems:Keele University<br>
> Finance & IT Directorate<br>
> Keele:Staffs:IC1 Building:ST5 5NB:UK<br>
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> ______________________________<wbr>__________________<br>
><br>
> On 15 February 2017 at 18:56, Nir Soffer <<a href="mailto:nsoffer@redhat.com">nsoffer@redhat.com</a>> wrote:<br>
>><br>
>> On Wed, Feb 15, 2017 at 2:32 PM, Gary Lloyd <<a href="mailto:g.lloyd@keele.ac.uk">g.lloyd@keele.ac.uk</a>> wrote:<br>
>> > Hi<br>
>> ><br>
>> > We currently use direct lun for our virtual machines and I would like to<br>
>> > move away from doing this and move onto storage domains.<br>
>> ><br>
>> > At the moment we are using an ISCSI SAN and we use on replicas created<br>
>> > on<br>
>> > the SAN for disaster recovery.<br>
>> ><br>
>> > As a test I thought I would replicate an existing storage domain's<br>
>> > volume<br>
>> > (via the SAN) and try to mount again as a separate storage domain (This<br>
>> > is<br>
>> > with ovirt 4.06 (cluster mode 3.6))<br>
>><br>
>> Why do want to replicate a storage domain and connect to it?<br>
>><br>
>> > I can log into the iscsi disk but then nothing gets listed under Storage<br>
>> > Name / Storage ID (VG Name)<br>
>> ><br>
>> ><br>
>> > Should this be possible or will it not work due the the uids being<br>
>> > identical<br>
>> > ?<br>
>><br>
>> Connecting 2 storage domains with same uid will not work. You can use<br>
>> either<br>
>> the old or the new, but not both at the same time.<br>
>><br>
>> Can you explain how replicating the storage domain volume is related to<br>
>> moving from direct luns to storage domains?<br>
>><br>
>> If you want to move from direct lun to storage domain, you need to create<br>
>> a new disk on the storage domain, and copy the direct lun data to the new<br>
>> disk.<br>
>><br>
>> We don't support this yet, but you can copy manually like this:<br>
>><br>
>> 1. Find the lv of the new disk<br>
>><br>
>> lvs -o name --select "{IU_<new-disk-uuid>} = lv_tags" vg-name<br>
>><br>
>> 2. Activate the lv<br>
>><br>
>> lvchange -ay vg-name/lv-name<br>
>><br>
>> 3. Copy the data from the lun<br>
>><br>
>> qemu-img convert -p -f raw -O raw -t none -T none<br>
>> /dev/mapper/xxxyyy /dev/vg-name/lv-name<br>
>><br>
>> 4. Deactivate the disk<br>
>><br>
>> lvchange -an vg-name/lv-name<br>
>><br>
>> Nir<br>
><br>
><br>
</div></div><div class="HOEnZb"><div class="h5">______________________________<wbr>_________________<br>
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