[Lxc-users] [MySQL] Weird performances problem between containers on a same host

[Mauras Olivier]

Also, bandwidth between containers is very bad...
scp a file doesn't get over 2.1MB/s - On gigabit interface - and drop over
time.

On Thu, Aug 11, 2011 at 9:32 AM, Mauras Olivier <oliver.mauras at gmail.com>wrote:

> So here's my results.
> On 55 packets transmitted for the mysql request
> 25 correct checksums
> 28 incorrect
>
> Disabling TSO and GSO doesn't help much, got exact same result
>
> As for the macvlan bridge mode how can i check if it's available or not??
> Would it let things work even if not supported?
> --- Misc ---
> Veth pair device: enabled
> Macvlan: enabled
> Vlan: enabled
> File capabilities: enabled
>
>
> Thanks,
> Olivier
>
>
>
> On Wed, Aug 10, 2011 at 6:25 PM, Daniel Lezcano <daniel.lezcano at free.fr>wrote:
>
>> On 08/10/2011 05:54 PM, Daniel Lezcano wrote:
>> > On 08/10/2011 04:51 PM, Mauras Olivier wrote:
>> >> Hello,
>> >>
>> >> I have several containers running on a host - ~10
>> >> One of them is running a MySQL database. Several of the others are
>> running
>> >> php code under apache that fetch datas from the database.
>> >>
>> >> Host is using eth0, while my containers are on a bridge using eth1, and
>> >> configured in macvlan bridge mode. Host runs SL6 with 2.6.32 RH kernel
>> -
>> >> Host is a VMWare ESX virtual machine for that matter.
>> >> Ping latency between containers is at an average of 0.050 ms
>> >>
>> >> What i noted, is that one webapp were getting very slow... After
>> >> investigating, the only thing that i could find, is that requests from
>> >> containers are _slower_ than from any other hosts.
>> >>
>> >> See below:
>> >>
>> >> container1 ~ # time (echo "select * from testsuites;" | mysql -h
>> >> container_mysql -u nmp -pxxx testlink)
>> >> id      details
>> >> 42
>> >> (... cut only 25 entries anyway)
>> >>
>> >> real    *0m0.875s*
>> >>
>> >> Time varies between 0.8 and 1.2s
>> >>
>> >> >From the host or another VM on the same network with the exact same
>> request:
>> >>
>> >> real    *0m0.022s*
>> >>
>> >>
>> >> So that particular app that can loop over 19 requests takes sometimes
>> up to
>> >> 20s to display a page instead of ~0.5s from another host...
>> >>
>> >> Is there some sysctl/settings to tweak or it's just not relevant to
>> make
>> >> requests between containers on the same host??
>> > Hmm, thanks for the detailed explanation.
>> >
>> > Can you check with tcpdump if there are problems with the patch
>> checksums ?
>> > And try to disable the TSO and SGO of eth1 if there are available ?
>>
>> Oh, and another question. AFAIK, the bridge mode is available since the
>> 2.6.33 kernel.
>> If we try to enable the bridge mode on a macvlan while this is not
>> supported, no error is reported.
>> So I don't know if the RH kernel did backport the bridge mode in their
>> .32 kernel.
>>
>
>
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