fuel-dev team mailing list archive

[Roman Sokolkov <rsokolkov@xxxxxxxxxxxx>]

Andrey,

What i know:

   1. KVM not maps directly vRAM to physical.So VM will use just as much as
   it needs.
   2. Red Hat recommends<https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/5/html/Virtualization/sect-Virtualization-Tips_and_tricks-Overcommitting_with_KVM.html>to
make swap partition with specific size to be protected from out of
   memory cases.

   (0.5 * RAM) + (overcommit ratio * RAM) = Recommended swap size


I think it is reasonable solution, because most of the loads are far from
100%. But i agree in case if 100% load applications it's reasonable to make
it <=1.

Thanks


On Sat, Apr 5, 2014 at 12:42 AM, Andrey Korolev <akorolev@xxxxxxxxxxxx>wrote:

> Just a small question - how the hell memory overcommit can be higher
> than 1? This will result in OOM and continuous weird behavior as soon
> as enough number of VMs will be launched.
>
> On Sat, Apr 5, 2014 at 3:02 AM, Roman Sokolkov <rsokolkov@xxxxxxxxxxxx>
> wrote:
> > Just small update about overcommit ratios
> >
> > As recommended by Red Hat
> > vCPU/CPU (cpu_allocation_ratio) = 5 (default 16)
> > vRAM/RAM (ram_allocation_ratio) = 1.5
> >
> > Thanks.
> >
> >
> >
> > On Fri, Apr 4, 2014 at 1:04 PM, Roman Sokolkov <rsokolkov@xxxxxxxxxxxx>
> > wrote:
> >>
> >> Folks,
> >>
> >> Any updates on that?
> >> Customers that run Fuel for production exactly need finely tuned
> >> scheduler.
> >> My two latest projects were affected by default "RAW" scheduling.
> >>
> >> Thank you.
> >>
> >>
> >> On Fri, Mar 21, 2014 at 7:18 AM, Bogdan Dobrelya <
> bdobrelia@xxxxxxxxxxxx>
> >> wrote:
> >>>
> >>> On 03/21/2014 03:04 PM, Dmitry Ukov wrote:
> >>> > Core and Disk  filters should be enabled (they are disabled by
> default)
> >>> > in order to avoid compute node oveloading
> >>> > - cpu_allocation_ratio=1.0 - was customer requirement. I think 16.0
> is
> >>> > way to big over commit ratio (potentially 16 vms on 1 core). I would
> >>> > say
> >>> > 2.0 or 3.0 will be reasonable here.
> >>> > - disk_allocation_ratio=1.0 - it is unsafe to over commit disk
> >>> > - ram_allocation_ratio=1.0 - this was customer requirement. Actually
> we
> >>> > can use default value here. (AFAIR default is 1.5 )
> >>> > - ram_weight_multiplier=0.0 and scheduler_host_subset_size=30 will
> help
> >>> > us to get random VMs distribution if compute nodes significantly
> differ
> >>> > from each other in terms of total RAM amount
> >>>
> >>> Thank you, that makes sense. I vote for enable these ones (leaving the
> >>> ram_allocation_ratio defaults) for Fuel nova manifests for Puppet. That
> >>> do you think?
> >>>
> >>> >
> >>> >
> >>> >
> >>> > On Thu, Mar 20, 2014 at 2:58 PM, Bogdan Dobrelya
> >>> > <bdobrelia@xxxxxxxxxxxx
> >>> > <mailto:bdobrelia@xxxxxxxxxxxx>> wrote:
> >>> >
> >>> >     On 03/20/2014 08:47 AM, Mike Scherbakov wrote:
> >>> >     > Hi Dmitry,
> >>> >     > I was running through bp created by
> >>> >     > you:
> >>> >
> >>> >
> https://blueprints.launchpad.net/fuel/+spec/scheduler-config-improvements.
> >>> >     >
> >>> >
> >>> >     Interesting, why CPU overcommitment defaults (
> >>> >
> >>> >
> https://github.com/openstack/nova/blob/master/etc/nova/nova.conf.sample#L1759
> >>> >     ) are so 'bad' to being changed so drastically 16->1?
> >>> >
> >>> >     > I'm wondering whether this config will work fine for every
> >>> >     installation
> >>> >     > we do with Fuel.. what are the possible limitations / corner
> >>> > cases?
> >>> >     >
> >>> >     > Thanks,
> >>> >     > --
> >>> >     > Mike Scherbakov
> >>> >     > #mihgen
> >>> >     >
> >>> >     >
> >>> >
> >>> >
> >>> >     --
> >>> >     Best regards,
> >>> >     Bogdan Dobrelya,
> >>> >     Skype #bogdando_at_yahoo.com <http://bogdando_at_yahoo.com>
> >>> >     Irc #bogdando
> >>> >
> >>> >
> >>> >
> >>> >
> >>> > --
> >>> > Kind regards
> >>> > Dmitry Ukov
> >>> > IT Engineer
> >>> > Mirantis, Inc.
> >>> >
> >>>
> >>>
> >>> --
> >>> Best regards,
> >>> Bogdan Dobrelya,
> >>> Skype #bogdando_at_yahoo.com
> >>> Irc #bogdando
> >>>
> >>> --
> >>> Mailing list: https://launchpad.net/~fuel-dev
> >>> Post to     : fuel-dev@xxxxxxxxxxxxxxxxxxx
> >>> Unsubscribe : https://launchpad.net/~fuel-dev
> >>> More help   : https://help.launchpad.net/ListHelp
> >>
> >>
> >>
> >>
> >> --
> >> Roman Sokolkov,
> >> Deployment Engineer,
> >> Mirantis, Inc.
> >> Skype rsokolkov,
> >> rsokolkov@xxxxxxxxxxxx
> >
> >
> >
> >
> > --
> > Roman Sokolkov,
> > Deployment Engineer,
> > Mirantis, Inc.
> > Skype rsokolkov,
> > rsokolkov@xxxxxxxxxxxx
> >
> > --
> > Mailing list: https://launchpad.net/~fuel-dev
> > Post to     : fuel-dev@xxxxxxxxxxxxxxxxxxx
> > Unsubscribe : https://launchpad.net/~fuel-dev
> > More help   : https://help.launchpad.net/ListHelp
> >
>



-- 
Roman Sokolkov,
Deployment Engineer,
Mirantis, Inc.
Skype rsokolkov,
rsokolkov@xxxxxxxxxxxx