Open Stack

On Tue, Sep 20, 2016 at 09:20:15AM -0400, Sean Dague wrote:
> This is a bit delayed due to the release rush, finally getting back to
> writing up my experiences at the Ops Meetup.
> 
> Nova Feedback Session
> =====================
> 
> We had a double session for Feedback for Nova from Operators, raw
> etherpad here - https://etherpad.openstack.org/p/NYC-ops-Nova.
> 
> The median release people were on in the room was Kilo. Some were
> upgrading to Liberty, many had older than Kilo clouds. Remembering
> these are the larger ops environments that are engaged enough with the
> community to send people to the Ops Meetup.
> 
> 
> Performance Bottlenecks
> -----------------------
> 
> * scheduling issues with Ironic - (this is a bug we got through during
>   the week after the session)
> * live snapshots actually end up performance issue for people
> 
> The workarounds config group was not well known, and everyone in the
> room wished we advertised that a bit more. The solution for snapshot
> performance is in there
> 
> There were also general questions about what scale cells should be
> considered at.
> 
> ACTION: we should make sure workarounds are advertised better

Workarounds ought to be something that admins are rarely, if
ever, having to deal with.

If the lack of live snapshot is such a major performance problem
for ops, this tends to suggest that our default behaviour is wrong,
rather than a need to publicise that operators should set this
workaround.

eg, instead of optimizing for the case of a broken live snapshot
support by default, we should optimize for the case of working
live snapshot by default. The broken live snapshot stuff was so
rare that no one has ever reproduced it outside of the gate
AFAIK.

IOW, rather than hardcoding disable_live_snapshot=True in nova,
we should just set it in the gate CI configs, and leave it set
to False in Nova, so operators get good performance out of the
box.

Also it has been a while since we added the workaround, and IIRC,
we've got newer Ubuntu available on at least some of the gate
hosts now, so we have the ability to test to see if it still
hits newer Ubuntu. 


Regards,
Daniel
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