IO Wait very high and real IO speed is very low

[Tang Jianwei]

Hi Marty,

thank you very much for your reply and the following is the files you 
are asking

/var/log/kern.log (should be the same as what you were asking)
http://pastebin.com/3fC1qxrq

/var/log/dmesg
http://pastebin.com/G059cxXN

output of the commands
http://pastebin.com/6faPXt43

And thank you very much in advance for your great help.


Best Regards
Tomas

On 2014/2/28 20:00, ubuntu-users-request at lists.ubuntu.com wrote:
> Message: 3
> Date: Fri, 28 Feb 2014 08:00:31 +0000
> From: Marty Sweet <msweet.dev at gmail.com>
> To: "Ubuntu user technical support, not for general discussions"
> 	<ubuntu-users at lists.ubuntu.com>
> Subject: Re: IO Wait very high and real IO speed is very low
> Message-ID:
> 	<CALoaWF5ACbWc=wwEiv4WorQZu0gpSEpk0UUSLMX6QhqnO1-m+w at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Hi Tomas,
>
> Could you provide the output of /var/log/kernel.log and /var/log/dmesg
> and $ df -h and $ fdisk -l ?
> When the problem occurs, can you also run $ ps aux ?
>
> Once you have done this please post it on pastebin and send the link,
> as there will be a few hundred lines.
>
> Thanks,
> Marty
>
> On Fri, Feb 28, 2014 at 6:00 AM, Tang Jianwei <myhnet at gmail.com> wrote:
>> Hi All,
>>
>>      recently I get a very weird problem from my Ubuntu Server 1204 LTS
>> 64bit:
>>      1. the write speed can reach 500MB/s when there is no other processes
>> running
>>      2. the write speed down to around 10MB/s when there are many other
>> processes and meanwhile:
>>              a. only very high usage from io wait
>>              b. sys, user and all the other cpu usages are very low
>>              c. the system load average can reach to 15 and even more higher
>>
>>      can any one give me some advice what is wrong with my system, and what I
>> should to adjust in hardware/software?
>>
>>      the platform is:
>>      MB: Intel S3240GPLC
>>      CPU: I3-540
>>      RAM: Kingston 4G ECC
>>      Storage: LSI MegaRaid 9270-8i, Raid 5 with 5 drives + 1 spare, ForcedWB
>> with no BBU
>>      Drive: WD 3T
>>
>>
>>      thank you very much.
>>
>>
>> Best Regards
>> Tomas
>>
>>
>>
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>