+1 on avoiding averages / using histograms. A similar write up to Baron's post below on the subject at http://www.circonus.com/problem-math/, in case you need more convincing :-)
Robert Treat On Wed, Dec 23, 2015 at 3:58 AM, Dan Vatca <[email protected]> wrote: > 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 > > > On Wed, Dec 23, 2015 at 2:44 AM, 張峻宇 <[email protected]> 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 >> >> >> >> >> >> 本信件可能包含中華電信股份有限公司機密資訊,非指定之收件者,請勿蒐集、處理或利用本信件內容,並請銷毀此信件. >> 如為指定收件者,應確實保護郵件中本公司之營業機密及個人資料,不得任意傳佈或揭露,並應自行確認本郵件之附檔與超連結之安全性,以共同善盡資訊安全與個資保護責任. >> Please be advised that this email message (including any attachments) >> contains confidential information and may be legally privileged. If you are >> not the intended recipient, please destroy this message and all attachments >> from your system and do not further collect, process, or use them. Chunghwa >> Telecom and all its subsidiaries and associated companies shall not be >> liable for the improper or incomplete transmission of the information >> contained in this email nor for any delay in its receipt or damage to your >> system. If you are the intended recipient, please protect the confidential >> and/or personal information contained in this email with due care. Any >> unauthorized use, disclosure or distribution of this message in whole or in >> part is strictly prohibited. Also, please self-inspect attachments and >> hyperlinks contained in this email to ensure the information security and to >> protect personal information. >> >> _______________________________________________ >> OmniOS-discuss mailing list >> [email protected] >> http://lists.omniti.com/mailman/listinfo/omnios-discuss >> > > > _______________________________________________ > OmniOS-discuss mailing list > [email protected] > http://lists.omniti.com/mailman/listinfo/omnios-discuss > _______________________________________________ OmniOS-discuss mailing list [email protected] http://lists.omniti.com/mailman/listinfo/omnios-discuss
