Open Stack

On 09/04/2014 01:51 PM, Juan José Pavlik Salles wrote:
> Hi Jay, I do agree about 10% being too much memory in big nodes, but
> right now we are using small ones (too small if you ask). These new
> nodes are 16GB so if I reserve 4 Gb for the dom0 I'd be loosing 25% of
> the available RAM. I was thinking about something like: if you have got
> less than 32GB give 10% of it to the dom0 and If you have got more than
> 32GB go with 4GB for the dom0.

I'd go with something like this:

  Host RAM           dom0/reserved host RAM
  ================== ======================
  16 - 32 GB	    2 GB
  32 - 64 GB         2.75 GB
  64 - 128 GB        3.50 GB
  128 - 256 GB       4.25 GB
  256+ GB            5.50 GB

If you have heavy packing of VMs (lots of tiny or small VMs), you may 
want to add a half GB to the above, but not much more than that, IMO)

 > Maybe different environments will need
> different rules, but this should work in most standar deployments I'd
> say. Jay, you mentioned that big nodes running many VMs don't neet more
> than 4GB of dedicated RAM, haven't you ever had any swapping situation
> in that kind of scenarios?

No, not on the compute nodes, no. On the controller nodes, yes, but 
that's a totally different thing :)

Best,
-jay

> 2014-09-04 14:26 GMT-03:00 Jay Pipes <jaypipes at gmail.com
> <mailto:jaypipes at gmail.com>>:
>
>     There's not really any need for 10% in my experience. Giving
>     dom0/bare metal around 3-4GB is perfectly fine for the vast majority
>     of scenarios, even when there's a hundred or more VMs on the box.
>     Most compute node server hardware nowadays should have 128-512GB of
>     RAM available, and 4GB for the host is more than enough.
>
>     -jay
>
>
>     On 09/04/2014 12:45 PM, Juan José Pavlik Salles wrote:
>
>         Hi Tomasz, thanks for your answer. I'll start with 10% and see what
>         happens. Thanks again!
>
>
>         2014-09-04 13:37 GMT-03:00 Tomasz Napierala
>         <tnapierala at mirantis.com <mailto:tnapierala at mirantis.com>
>         <mailto:tnapierala at mirantis.__com
>         <mailto:tnapierala at mirantis.com>>>:
>
>
>
>              On 04 Sep 2014, at 18:04, Juan José Pavlik Salles
>              <jjpavlik at gmail.com <mailto:jjpavlik at gmail.com>
>         <mailto:jjpavlik at gmail.com <mailto:jjpavlik at gmail.com>>> wrote:
>
>               > Hi guys, I'm running a Grizzly cloud with Ubuntu
>         12.04+KVM. I'd
>              like to know if there's any kind of recommended free RAM
>         for the
>              Hypervisor. I know there's a nova variable called "
>               > reserved_host_memory_mb" but don't know what a proper
>         value would be.
>
>              Check on deployed compute node that has no running VMs, add
>         some
>              margin, say 10% and you should be fine. Usually compute
>         nodes are
>              not consuming extra memory besides VMs.
>
>              Regards,
>              --
>              Tomasz 'Zen' Napierala
>              Sr. OpenStack Engineer
>         tnapierala at mirantis.com <mailto:tnapierala at mirantis.com>
>         <mailto:tnapierala at mirantis.__com <mailto:tnapierala at mirantis.com>>
>
>
>
>
>
>
>
>
>
>
>         --
>         Pavlik Salles Juan José
>         Blog - http://viviendolared.blogspot.__com
>         <http://viviendolared.blogspot.com>
>
>
>         _________________________________________________
>         OpenStack-operators mailing list
>         OpenStack-operators at lists.__openstack.org
>         <mailto:OpenStack-operators at lists.openstack.org>
>         http://lists.openstack.org/__cgi-bin/mailman/listinfo/__openstack-operators
>         <http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators>
>
>
>     _________________________________________________
>     OpenStack-operators mailing list
>     OpenStack-operators at lists.__openstack.org
>     <mailto:OpenStack-operators at lists.openstack.org>
>     http://lists.openstack.org/__cgi-bin/mailman/listinfo/__openstack-operators
>     <http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators>
>
>
>
>
> --
> Pavlik Salles Juan José
> Blog - http://viviendolared.blogspot.com