[DRBD-user] DM to Linstor migration issue

[Roberto Resoli]

Il 21/08/2018 11:23, Robert Altnoeder ha scritto:
> On 08/21/2018 09:23 AM, Yannis Milios wrote:
>> Checked the error reports that are listed by using the 'linstor
>> error-reports list', and I can see multiple occurrences of the
>> following error:
>> Description:
>>      Initialization of storage for resource 'vm-115-disk-1' volume 0 failed
>> Cause:
>>      Storage volume 0 of resource 'vm-115-disk-1' too large. Expected
>> 33561640KiB, but was : 33587200KiB.

more or less the same here

=== /var/log/linstor-satellite/ErrorReport-5B7BC584-000001.log ===
Error message:                      Initialization of storage for 
resource 'vm-101-disk-2' volume 0 failed
Error message:                      Storage volume 0 of resource 
'vm-101-disk-2' too large. Expected 104880044KiB, but was : 104960000KiB.


> I guess that may have been caused by a different peer count in drbdmanage.
> Volumes are defined by net size (usable size) in drbdmanage and LINSTOR,
> but the actual backend storage is larger than the net size due to
> internal DRBD meta data. One of the factors that the size of DRBD meta
> data depends on is the number of peer slots.

I checked with

lvs --units k

and the size was as reported by linstor-satellite error report (after 
"but was:")

> You could try to resize the volume (volume-definition set-size) to match
> those 33587200 KiB that you see as the expected value, which will
> effectively make it somewhat larger than that. 

I did that and the resource came online and started sync

> If the peer count is
> indeed different from what LINSTOR thinks it should be, that might cause
> a mismatch between the net size reported by LINSTOR and the actual net
> size, but it should at least make the volume usable until we can come up
> with a fix for any issues caused by different peer count.
> 
> You could also try to figure out the actual peer count of that resource
> and attempt to set the correct peer count on the LINSTOR
> resource-definition, volume-definition, on each resource/volume or
> something like that - I am not sure that it will let you after the
> resources have been created though. We might need to fix this in the
> migration script.

Yes; anyway after all I managed to complete the migration with some 
manual intervention.

I guess I can safely delete .drbdctrl volume now ...

Thanks,
rob