[ovirt-users] DR with oVirt: no data on OVF_STORE

[Yaniv Kaul]

On Fri, Sep 29, 2017 at 6:06 PM, Luca 'remix_tj' Lorenzetto <
lorenzetto.luca at gmail.com> wrote:

> Hello,
>
> i'm experimenting a DR architecture that involves block storage
> replication from the storage side (EMC VNX 8000).
>
> Our idea is to import the replicated data storage domain on another
> datacenter, managed by another engine, with the option "Import Domain"
> and then import all the vms contained.
>
> The idea works, but we encountered an issue that we don't want to have
> again: we imported an SD and *no* vm were listed in the tab "VM
> Import". Disks were available, but no VM informations.
>
> What we did:
>  - on storage side: split the replica between the main disk in Site A
> and the secondary disk Site B
>  - on storage side: added the disk to the storage group of the
> "recovery" cluster
>  - from engine UI: Imported storage domain, confirming that i want to
> activate even if seems to be attached to another DC
>  - from engine UI: move out from maintenance the storage domain and
> click on the "VM Import" tab of the new SD.
>
> What happened: *no* vm were listed
>
> To identify better what's happening, I've found here some indications
> on how lvm for block storage works and I identified the command on how
> to find and read the OVF_STORE.
> Looking inside the OVF_STORE has shown why no vm were listed: it was
> empty (no .ovf file listed with tar tvf)
>
> So, without the possibility import vms, i did a rollback, detaching
> the storage domain and re-establishing the replication between the
> main site and the DR site.
>
> Then, after a day of replications (secondary volume is  aligned every
> 30 minutes), i tried again and i've been able to import also vms
> (OVF_STORE was populated).
>
> So my question is: how to i force to have OVF_STORE to be aligned at
> least as frequent as the replication? I want to have the VM disks
> replicated to the remote site along with VM OVF informations.
>

1. There are events when the OVF store is updated.
2. You can force via the API:
POST api/storagedomains/{sd_id}/updateovfstore
3. You can right-click on a storage domain and select 'Update OVFs'
4. You can reduce the frequency in which it is updated (1h by default). I
do not recommend reducing it too much. OvfUpdateIntervalInMinutes I believe
is the engine-config key for it.
Y.



>
> Is possible to have OVF_STORE informations aligned when a VM is
> created/edited or with a scheduled task? Is this so I/O expensive?
>
> Thank you,
>
>
> Luca
>
>
>
> --
> "E' assurdo impiegare gli uomini di intelligenza eccellente per fare
> calcoli che potrebbero essere affidati a chiunque se si usassero delle
> macchine"
> Gottfried Wilhelm von Leibnitz, Filosofo e Matematico (1646-1716)
>
> "Internet è la più grande biblioteca del mondo.
> Ma il problema è che i libri sono tutti sparsi sul pavimento"
> John Allen Paulos, Matematico (1945-vivente)
>
> Luca 'remix_tj' Lorenzetto, http://www.remixtj.net , <
> lorenzetto.luca at gmail.com>
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>
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