Hi,
This is just a tip, I do not know if this actually applies to you, but
some ssds are decreasing their write throughput on purpose so they do
not wear out the cells before the warranty period is over.
Denes.
On 12/17/2017 06:45 PM, shadow_lin wrote:
Hi All,
I am testing luminous 12.2.2 and find a strange behavior of my cluster.
I was testing my cluster throughput by using fio on a mounted
rbd with follow fio parameters:
fio -directory=fiotest -direct=1 -thread -rw=write -ioengine=libaio
-size=200G -group_reporting -bs=1m -iodepth 4 -numjobs=200 -name=writetest
Everything was fine at the begining, but after about 10 hrs of testing
I found the performance dropped noticeably.
Throughput droped from 300-450MBps to 250-350MBps and osd latency
increased from 300ms to 400ms
I also noted the heap stats showed the osd start
reclaiming page heap freelist much more frequently but the rss memory
of osd were increasing.
below is the links of grafana graph of my cluster.
cluster metrics: https://pasteboard.co/GYEOgV1.jpg
osd mem metrics: https://pasteboard.co/GYEP74M.png
In the graph the performance dropped after 10:00.
I am investigating what happened but haven't found any clue yet.
If you know any thing about how to solve this problem or where I
should look into please let me know.
Thanks.
2017-12-18
------------------------------------------------------------------------
lin.yunfan
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