Re: Swap usage with KVM

[Rik van Riel <riel@redhat.com>]

On 08/02/2010 02:57 PM, Daniel Bareiro wrote:
> Hi, Rik.
>
> On Sunday, 11 July 2010 17:49:43 -0400,
> Rik van Riel wrote:
>
>>>> I have an installation with Debian GNU/Linux 5.0.4 amd64 with
>>>> qemu-kvm 0.12.3 compiled with the source code obtained from the
>>>> official site of KVM and Linux 2.6.32.12 compiled from source code
>>>> of kernel.org. All this is installed on an HP Proliant DL380 G6 with
>>>> two Xeon E5530 quadcore processors and 16 GiB of RAM which has two
>>>> VMs with the following configuration of memory:
>>>>
>>>> Hostname       |      RAM
>>>> ===============+===============
>>>> Aps4           |    7 GiB
>>>> Leela          |    7 GiB
>>>> ===============+===============
>>>> TOTAL          |   14 GiB
>>>>
>>>> Initially the host was created with a swap partition of 1 GiB, but
>>>> today we found that the use of swap quickly began to grow
>>>> increasingly.  Therefore, as a contingency, we had to hot-add a
>>>> logical volume of 1 GB of swap on the VMHost. Is 'normal' this use
>>>> of memory?
>
>> That depends on what is going on in the host.
>>
>> Did you notice any performance issues in the guest when you started
>> using swap?
>
> After the logical volume of 1 GB that I added when I found this problem
> (being the operating system with 2 GB), I added other 3 GB to have a
> little more margin, but today I got again a new alert of Nagios:
>
>
> Swap usage     WARNING    [...]    SWAP WARNING - 30% free   (1490 MB out of 5052 MB)
>
>
> I don't see performance issue in the VMs.
>
> Marcelo Tosatti recommended me to apply the EPT patch
> (6316e1c8c6af6ccb55ff8564231710660608f46c). Should it be safe for use in
> production? Are there plans that this patch is applied on some version
> of Linux stable?

Yes, that patch is safe and definitely recommended.

-- 
All rights reversed