[ovirt-users] high number of IOPS from ovirt hosts

[Andrea Ghelardi]

Andrea,
I don't want to point any fingers but Mark Greenall faced some issues with Ovirt 4.06/4.1 linked to equallogic as well.
You may want to search posts in this ML with subject " Ovirt 4.0.6 guests 'Not Responding' " to see if you find any similarities.
How many storages are you presenting to how many clusters?
Also, are your nodes all Hosted Engine Hosts? In my old configuration, normal hosts read IOPS ranged from 50 to 500 while HE ones peaked even ~3000
Cheers
AG


-----Original Message-----
From: Andrea Fagiani [mailto:andrea.fagiani at immobiliare.it] 
Sent: Friday, February 10, 2017 5:56 PM
To: Andrea Ghelardi <a.ghelardi at iontrading.com>; users at ovirt.org
Subject: Re: [ovirt-users] high number of IOPS from ovirt hosts

Hi Andrea,

thanks for the insight; no I wasn't able to pinpoint the issue to a single host, the load seems to be evenly spread.
We have another cluster running 4.0.6 on a compellent as well and we haven't experienced any similar issues.

Thanks,
Andrea


On 10/02/2017 17:17, Andrea Ghelardi wrote:
> Hello Andrea,
> I saw that happening on my HE hosts connected to a COMPELLENT SC040 
> when I was running Ovirt 3.5
>
> All HE hosts were hammering the SAN with 2~4k IOPS each
>
> Upgrading to 4.0.5 solved my case.
> Are you able to check if IOPS are generated from a particular host or rather spread among all nodes?
>
> Cheers
> AG
>
>
> -----Original Message-----
> From: users-bounces at ovirt.org [mailto:users-bounces at ovirt.org] On 
> Behalf Of Andrea Fagiani
> Sent: Friday, February 10, 2017 12:47 PM
> To: users at ovirt.org
> Subject: [ovirt-users] high number of IOPS from ovirt hosts
>
> Hi,
>
> We've got a 8-host cluster running oVirt 4.1; each host is connected via iscsi to a EQL 4100 storage (2x).
> Most of the VMs use barely any IOPS, however on our storage controller we've noticed a constant steam of reads, about 2000 IOPS; any idea what might cause the ovirt hosts to hammer on the storage so much?
>
> Looking at iotop, it seems that systemd-udevd is being activated every few seconds (and its IO% is usually fairly high) so I assume this might be somehow related.
>
> Thanks,
> Andrea
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