hello pavel,
Thanks for you answer.
I did find this parameter (only) in /etc/vdsm/vdsm.conf.rpmnew (??)
Parameter is commented with value 2 so my guess is that it is not used... So
this brings a few more questions :
- Since parameter is commented, default value must be used... can we be sure
that 2 is default value?
I do found strange that migrations are limited to 2, I have the feeling that
more than two are simultaneously being migrated (but I'm maybe wrong), how to
be sure?
cordialement, regards,
Nelson LAMEIRAS
Ingénieur Systèmes et Réseaux / Systems and Networks engineer
Tel: +33 5 32 09 09 70
nelson.lamei...@lyra-network.com
www.lyra-network.com | www.payzen.eu
Lyra Network, 109 rue de l'innovation, 31670 Labège, FRANCE
From: "Pavel Gashev" <p...@acronis.com>
To: users@ovirt.org, "nelson lameiras" <nelson.lamei...@lyra-network.com>
Sent: Tuesday, April 18, 2017 7:16:08 PM
Subject: Re: [ovirt-users] massive simultaneous vms migrations ?
VDSM has the following config option:
# Maximum concurrent outgoing migrations
# max_outgoing_migrations = 2
On Tue, 2017-04-18 at 18:48 +0200, Nelson Lameiras wrote:
hello,
When putting a host on "maintenance mode", all vms start migrating to other
hosts.
We have some hosts that have 60 vms. So this will create a 60 vms migrating
simultaneously.
Some vms are under so much heavy loads that migration fails often (our guess is
that massive simultaneous migrations does not help migration convergence) -
even with "suspend workload if needed" migraton policy.
- Does oVirt really launches 60 simultaneous migrations or is there a queuing
system ?
- If there is a queuing system, is there a way to configure a maximum number of
simultaneous migrations ?
I did see a "migration bandwidth limit", but this is quite what we are looking
for.
my setup:
ovirt-engine +hosted engine 4.1.1
hosts : centos 7.3 fully updated.
for full context to understand this question : 2 times in the past, when trying
to put a host in maintenance, host stopped responding during massive migrations
and was fenced by engine. It's still unclear why host stopped responding, but
we think that migrating 60+ vms simultaneously puts a heavy strain on storage ?
So we would like to better control migration process in order to better
understand what's happening. This scenario is "production only" since our labs
do not contain nearly as much vm with such heavy loads. So rather than trying
to reproduce, we are trying to avoid ;)
cordialement, regards,
Nelson LAMEIRAS
Ingénieur Systèmes et Réseaux / Systems and Networks engineer
Tel: +33 5 32 09 09 70
nelson.lamei...@lyra-network.com
www.lyra-network.com | www.payzen.eu
Lyra Network, 109 rue de l'innovation, 31670 Labège, FRANCE
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