Open Stack

On Thu, Mar 19, 2020, at 1:25 AM, Arnaud Morin wrote:
> 
> Hey Melanie, all,
> 
> About OVH case (company I work for).
> We are digging into the issue.
> 
> First thing, we do not limit anymore the IOPS. I dont remember when we
> removed this limit, but this is not new.
> 
> However, the hypervisor are quite old now, and our policy on this old
> servers was to use some swap.
> And we think that the host may slow down when overcommitting on RAM
> (swapping on disk).
> 
> Anyway, we also know that we can have better latency when upgrading
> QEMU. We are currently in the middle of testing a new QEMU version, I
> will push to upgrade your hypervisors first, so we will see if the
> latency on QEMU side can help the gate.
> 
> Finally, we plan to change the hardware and stop doing overcommit on RAM
> (and swapping on disk). However, I have no ETA about that, but for sure,
> this will improve the IOPS.

You all likely know far more about this than I do, but our use case is likely ideal for kernel same page merging because we boot a relatively small number of identical images that rotate relatively slowly (24 hours). Turning that on, if not already, could potentially reduce memory pressure.

> 
> I'll keep you in touch.
> 
> Cheers,
> 
> -- 
> Arnaud Morin
>