[OmniOS-discuss] How to get NFS read & write latency in OmniOS r151016

[Dan Vatca]

If you need latency, you will most likely need a latency distribution
histogram, and not an average latency.
With averages you will lose latency outliers that are very important.
Here's a good read with lots of references on this topic:
https://www.vividcortex.com/blog/why-percentiles-dont-work-the-way-you-think
To currently do this on OmniOS, you need to use dtrace to aggregate
(quantize) time differences between nfsv3:::op-read-start
and nfsv3:::op-read-done (same for write).


Dan Vâtca

CTO at Syneto

Tel: +40723604357, Skype: dan_vatca

<http://www.syneto.net/>

On Wed, Dec 23, 2015 at 2:44 AM, 張峻宇 <jerry1209 at cht.com.tw> wrote:

> Hi all,
>
>       According to the release note of OmniOS r151016, we could get “IOPS,
> bandwidth, and latency kstats for NFS server”
>
>
>
>       there is lots of information showing when I use enter command #kstat,
>
>       I want to get the “nfs read & write latency for NFS server”
>
>
>
>       Q1 : Is the ‘nfs:0:rfsprocio_v4_write:wtime’ &
> ‘nfs:0:rfsprocio_v4_read:wtime’ meant write & read latency ?
>
>       Q2 : I mounted the nfs share directory, and write lots file to it,
> the number of ‘nfs:0:rfsprocio_v4_write:wtime’ &
> ‘nfs:0:rfsprocio_v4_read:wtime’ still zero. Why ?
>
>
>
>       #kstat –p –m nfs –n rfsprocio_v4_write
>
>         nfs:0:rfsprocio_v4_write:class        rfsprocio_v4
>
> nfs:0:rfsprocio_v4_write:crtime     50.833043074
>
> nfs:0:rfsprocio_v4_write:nread      3932160
>
> nfs:0:rfsprocio_v4_write:nwritten  5374607360
>
> nfs:0:rfsprocio_v4_write:rcnt 0
>
> nfs:0:rfsprocio_v4_write:reads       163840
>
> nfs:0:rfsprocio_v4_write:rlastupdate     12048225488385
>
> nfs:0:rfsprocio_v4_write:rlentime  33429565743
>
> nfs:0:rfsprocio_v4_write:rtime       23992279289
>
> nfs:0:rfsprocio_v4_write:snaptime 269635.483575440
>
> nfs:0:rfsprocio_v4_write:wcnt        0
>
> nfs:0:rfsprocio_v4_write:wlastupdate    0
>
> nfs:0:rfsprocio_v4_write:wlentime 0
>
> nfs:0:rfsprocio_v4_write:writes      163840            / number of writes /
>
> nfs:0:rfsprocio_v4_write:wtime     0                      / wait queue -
> time spent waiting /
>
>
>
>         #kstat –p –m nfs –n rfsprocio_v4_read
>
>         nfs:0:rfsprocio_v4_read:class rfsprocio_v4
>
> nfs:0:rfsprocio_v4_read:crtime      50.833003263
>
> nfs:0:rfsprocio_v4_read:nread       0
>
> nfs:0:rfsprocio_v4_read:nwritten   0
>
> nfs:0:rfsprocio_v4_read:rcnt  0
>
> nfs:0:rfsprocio_v4_read:reads        0
>
> nfs:0:rfsprocio_v4_read:rlastupdate      0
>
> nfs:0:rfsprocio_v4_read:rlentime   0
>
> nfs:0:rfsprocio_v4_read:rtime        0
>
> nfs:0:rfsprocio_v4_read:snaptime  269635.483080962
>
> nfs:0:rfsprocio_v4_read:wcnt 0
>
> nfs:0:rfsprocio_v4_read:wlastupdate     0
>
> nfs:0:rfsprocio_v4_read:wlentime 0
>
> nfs:0:rfsprocio_v4_read:writes       0
>
> nfs:0:rfsprocio_v4_read:wtime      0
>
>
>
>
>
>
>
> Best regards,
>
> ---------------------------------------------
>
> 張峻宇
>
> 中華電信研究院雲端運算研究所
>
> TEL: 03-4245663
>
>
>
>
>
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