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Re: Nova DB Connection Pooling

 

Sure ... was there something in particular you wanted to know about?

The overview:

The assumption with Zones is there is a single DB deployment per Zone. When I say "single DB", that could be clustered/HA as need be. But the intention is no sharing of DB between zones.

This, of course, has caused us some problems with respect to Instance/Flavor/User ID's being shared across zones. But these have largely been mitigated with the use of UUID's, Glance & Keystone. Not sure how Networks and Volumes will behave.

Data collected from child zones get encrypted blobs of data from the child that may contain ID's or zone-local information, but it's not generally available to the parent zones. They're ephemeral magic cookies.

We don't do a lot of disk access in the distributed scheduler. Most stuff is in-memory and transient.

-S

________________________________________
From: openstack-bounces+sandy.walsh=rackspace.com@xxxxxxxxxxxxxxxxxxx [openstack-bounces+sandy.walsh=rackspace.com@xxxxxxxxxxxxxxxxxxx] on behalf of Devin Carlen [devin.carlen@xxxxxxxxx]
Sent: Monday, September 26, 2011 10:26 PM
To: Soren Hansen
Cc: openstack@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Openstack] Nova DB Connection Pooling

We really need to hear from Sandy Walsh on this thread so he can elaborate on how the distributed scheduling works (with multiple mysql databases).

Devin


On Sep 26, 2011, at 6:41 AM, Soren Hansen wrote:

> 2011/9/26 Pitucha, Stanislaw Izaak <stanislaw.pitucha@xxxxxx>:
>> The pain starts when your max memory usage crosses what you have available.
>> Check http://dev.mysql.com/doc/refman/5.1/en/memory-use.html - especially comments which calculate the needed memory for N connections for both innodb and isam. (mysqltuner.pl will also calculate that for you)
>>
>> Hundreds of connections should be ok. Thousands... you should rethink it ;)
>
> Hm.. It doesn't take many racks full of blade servers to get into 4
> digit numbers of compute nodes. Certainly fewer than I was expecting
> to see in a garden variety Nova zone.
>
> --
> Soren Hansen        | http://linux2go.dk/
> Ubuntu Developer    | http://www.ubuntu.com/
> OpenStack Developer | http://www.openstack.org/
>
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