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Attila,

Thanks for the details.

Why the current Zk driver is not good ?

Apart from the slowness of Mc, Zk driver are they reliable enough ?

Lets say I have more than 1000 compute would you still suggest to go with
DB Servicegroup driver ?

>The sg drivers was introduced to eliminate 100 Update/sec at 1000 Host,
>but it caused all service is being fetched from the DB even if at the
given code
>part you just need to alive services.

Couldn't get this comment, current implementation has get_all and
service_is_up calls so why is it still fetching all compute nodes rather
than fetching only the ones which where service_is_up ?

-Vilobh

On Tue, Apr 28, 2015 at 12:34 AM, Attila Fazekas <afazekas at redhat.com>
wrote:

> How many compute nodes do you want to manage ?
>
> If it less than ~1000, you do not need to care.
> If you have more, just use SSD with good write IOPS value.
>
> Mysql actually can be fast with enough memory and good SSD.
> Even faster than [1].
>
> zk as technology is good, the current nova driver is not. Not recommended.
> The current mc driver does lot of tcp ping-pong for every node,
> it can be slower than the SQL.
>
> IMHO At high compute node count you would face with scheduler latency
> issues
> sooner than sg driver issues. (It is not Log(N) :()
>
> The sg drivers was introduced to eliminate 100 Update/sec at 1000 Host,
> but it caused all service is being fetched from the DB even if at the
> given code
> part you just need to alive services.
>
>
> [1]
> http://www.percona.com/blog/2013/10/18/innodb-scalability-issues-tables-without-primary-keys/
>
> ----- Original Message -----
> > From: "Vilobh Meshram" <vilobhmeshram.openstack at gmail.com>
> > To: "OpenStack Development Mailing List (not for usage questions)" <
> openstack-dev at lists.openstack.org>, "OpenStack
> > Mailing List (not for usage questions)" <openstack at lists.openstack.org>
> > Sent: Tuesday, April 28, 2015 1:21:58 AM
> > Subject: [openstack-dev] [openstack][nova] Does anyone use Zookeeper,
> Memcache Nova ServiceGroup Driver ?
> >
> > Hi,
> >
> > Does anyone use Zookeeper[1], Memcache[2] Nova ServiceGroup Driver ?
> >
> > If yes how has been your experience with it. It was noticed that most of
> the
> > deployment try to use the default Database driver[3]. Any experiences
> with
> > Zookeeper, Memcache driver will be helpful.
> >
> > -Vilobh
> >
> > [1]
> >
> https://github.com/openstack/nova/blob/master/nova/servicegroup/drivers/zk.py
> > [2]
> >
> https://github.com/openstack/nova/blob/master/nova/servicegroup/drivers/mc.py
> > [3]
> >
> https://github.com/openstack/nova/blob/master/nova/servicegroup/drivers/db.py
> >
> >
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