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Re: [Qemu-devel] 回复: 回复: 回复: qemu vm big network latency when met heav
From: |
Josh Durgin |
Subject: |
Re: [Qemu-devel] 回复: 回复: 回复: qemu vm big network latency when met heavy io |
Date: |
Mon, 13 Jan 2014 22:24:59 -0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 |
On 01/12/2014 06:39 PM, Stefan Hajnoczi wrote:
> On Fri, Jan 10, 2014 at 11:50 AM, 叶绍琛 <address@hidden> wrote:
>
> Please use Reply-all to keep the CC list in tact. That way the
> conversation stays on the mailing list and others can participate.
>
>>> Is the sum of guests' RAM less than the total physical RAM on the host
>> The host run 3 vms, each vm use one vcpu core and 1G ram.
>> # free -m
>>
>> total used free shared buffers cached
>>
>> Mem: 32242 4808 27434 0 278 2058
>>
>> -/+ buffers/cache: 2471 29771
>>
>> Swap: 4095 0 4095
>>
>>
>> The host has 8 cores.
>> # cat /proc/cpuinfo | grep processor
>> processor : 0
>> processor : 1
>> processor : 2
>> processor : 3
>> processor : 4
>> processor : 5
>> processor : 6
>> processor : 7
>>
>> so, both of two question's answer is 'yes'.
>> When I runing random write test, the host use 0 swap.
>
> Great. That means the host is not overcommitted.
>
> It's likely that the problem is a bug in QEMU's rbd driver or librados.
>
> Josh: Perhaps something you're interested in looking into?
Yes, thanks for bringing it to my attention. It does sound like a bug in
QEMU's rbd driver or ceph's userspace libraries.
Could you share what version of librbd you're using, and your
/etc/ceph/ceph.conf?
Thanks,
Josh