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 cachedMem: 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.
I find it indispensible these days.