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Re: Antw: Re: Slapd running very slow
On 2015-04-23 4:43 PM, Howard Chu wrote:
> Geoff Swan wrote:
>>
>>
>> On 2015-04-23 4:07 PM, Ulrich Windl wrote:
>>>>>> Geoff Swan <gswan3@bigpond.net.au> schrieb am 22.04.2015 um 23:18
>>>>>> in Nachricht
>>> <5538100A.3060301@bigpond.net.au>:
>>>
>>> [...]
>>>> Free stats look fine to me. No swap is being used, or has been used
>>>> yet
>>>> on this system.
>>>>
>>>> total used free shared buffers
>>>> cached
>>>> Mem: 132005400 21928192 110077208 10612 363064
>>>> 19230072
>>>> -/+ buffers/cache: 2335056 129670344
>>>> Swap: 8388604 0 8388604
>>>>
>>>> The effect I am seeing is that despite a reasonably fast disc system,
>>>> the kernel writing of dirty pages is painfully slow.
>>> So disk I/O stats is also available via sar. May we see them?
>>> Finally there's blktrace where you can follow the timing and
>>> positions of each individual block being written, but that's not
>>> quite easy to run and analyze (unless I missed the easy way).
>>>
>>> I suspect scattered writes that bring your I/O rate down.
>>>
>>> Regards,
>>> Ulrich
>>>
>> sysstat (and sar) is not installed on this system, so I can't give you
>> that output.
>
> As I said in my previous email - use iostat and/or vmstat to monitor
> paging activity and system wait time. You can also install atop and
> get all of the relevant stats on one screen.
>
> http://www.atoptool.nl/
>
> I find it indispensible these days.
>
Thanks, I'll look at buiding it. I have used nmon for a while to view
cpu/vm/mem/diskio stats at once.
The system is very lightly loaded at the moment.
# vmstat -w 2 10
procs ---------------memory-------------- ---swap-- -----io----
-system-- ------cpu-----
r b swpd free buff cache si so bi bo in
cs us sy id wa st
0 1 0 109758112 391744 19534916 0 0 3 25 3
2 2 0 97 1 0
0 0 0 109758304 391752 19534920 0 0 0 1160 1852
1360 1 0 97 2 0
1 1 0 109755448 391752 19534924 0 0 0 622 1899
1244 1 0 97 1 0
0 1 0 109755536 391752 19534928 0 0 0 2444 1917
1427 1 0 97 2 0
1 1 0 109756784 391756 19534940 0 0 0 116 4987
2658 3 1 96 1 0
3 1 0 109755440 391756 19534948 0 0 0 396 6009
3341 3 2 94 2 0
1 1 0 109756176 391760 19534964 0 0 0 306 6312
3260 3 2 94 1 0
0 1 0 109757840 391760 19534976 0 0 0 320 6120
3293 3 2 94 1 0
0 1 0 109755968 391760 19534984 0 0 0 222 4617
2569 2 1 96 1 0
1 1 0 109754528 391760 19534988 0 0 0 256 2002
1434 1 0 98 1 0