Den 29 nov. 2017 18:49 skrev Demeter Tibor <tdeme...@itsmart.hu>:
Hi,
Yes, I understand what do you talk about. It isn't too safe..:(
We have terrabytes under that VM.
I could make a downtime at most for eight hours (maybe), but meanwhile I have to copy 3 TB of vdisks. Firstly I need export (with a gigabit nic) to export domain, and back under 10gbe nic.
I don't know how is enough this.
Well, just counting the numbers, let's start with the optimistic approach and say that you can move 100 MB/s for 8 hours:
100*60*60*8=2880000 MB
And then just divide that with 1024*1024 to get to Tera:
2880000%(1024^2)=2.74658203125 TB
So roughly 2.7 TB in 8 hours, and that's very optimistic! If you're more pessimistic, adjust the number of MB you think (or better yet, tested) that you'll be able to send per second to get a more accurate answer.
The question is how much you can do without any downtime, I don't know myself, but the devs should:
@devs
Is it possible to do live exports? I mean to keep exporting and just sync the delta? If not, that would be an awesome RFE, since it would drastically reduce the downtime for these kinds of operations.
/K
Thanks
Tibor
----- 2017. nov.. 29., 18:26, Christopher Cox c...@endlessnow.com írta:
> On 11/29/2017 09:39 AM, Demeter Tibor wrote:
>>
>> Dear Users,
>>
>> We have an old ovirt3.5 install with a local and a shared clusters. Meanwhile we
>> created a new data center, that based on 4.1 and it use only shared
>> infrastructure.
>> I would like to migrate an big VM from the old local datacenter to our new, but
>> I don't have enough downtime.
>>
>> Is it possible to convert the old local storage to shared (by share via NFS) and
>> attach that as new storage domain to the new cluster?
>> I just want to import VM and copy (while running) with live storage migration
>> function.
>>
>> I know, the official way for move vms between ovirt clusters is the export
>> domain, but it has very big disks.
>>
>> What can I do?
>
> Just my opinion, but if you don't figure out a way to have occasional downtime,
> you'll probably pay the price with unplanned downtime eventually (and it could
> be painful).
>
> Define "large disks"? Terabytes?
>
> I know for a fact that if you don't have good network segmentation that live
> migrations of large disks can be very problematic. And I'm not talking about
> what you're wanting to do. I'm just talking about storage migration.
>
> We successfully migrated hundreds of VMs from a 3.4 to a 3.6 (on new blades and
> storage) last year over time using the NFS export domain method.
>
> If storage is the same across DC's, you might be able to shortcut this with
> minimal downtime, but I'm pretty sure there will be some downtime.
>
> I've seen large storage migrations render entire nodes offline (not nice) due to
> non-isolated paths or QoS.
>
>
>
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