Yes, good catch. By term of number of changed mapping (I sort and compared the OSD set), this patch do helps a lot as every remapped PG only has one OSD changing. Cool , well done. > -----Original Message----- > From: Xusangdi [mailto:xu.sangdi@xxxxxxx] > Sent: Monday, October 19, 2015 4:13 PM > To: Chen, Xiaoxi > Cc: ceph-devel@xxxxxxxxxxxxxxx > Subject: RE: chooseleaf may cause some unnecessary pg migrations > > I just realized the measurement I mentioned last time is not precise. It > should be 'number of changed mappings' instead of 'number of remapped > PGs'. > For example, [2,1,7] -> [0,7,4] should be regarded differently from [2,1,7] -> > [1,7,4], as the first change causes doubled data transfer. > Is this the reason for your test results? > > > -----Original Message----- > > From: Chen, Xiaoxi [mailto:xiaoxi.chen@xxxxxxxxx] > > Sent: Monday, October 19, 2015 3:34 PM > > To: Sage Weil; xusangdi 11976 (RD) > > Cc: ceph-devel@xxxxxxxxxxxxxxx > > Subject: RE: chooseleaf may cause some unnecessary pg migrations > > > > Thanks sage. > > > > Retesting by using --test --weight ${rand} 0 , still in 40 OSDs, 10 per host > case: > > > > New code average on 204.31 while old code average on 202.31 > > > > > > > -----Original Message----- > > > From: Sage Weil [mailto:sage@xxxxxxxxxxxx] > > > Sent: Monday, October 19, 2015 10:18 AM > > > To: Xusangdi > > > Cc: Chen, Xiaoxi; ceph-devel@xxxxxxxxxxxxxxx > > > Subject: RE: chooseleaf may cause some unnecessary pg migrations > > > > > > On Mon, 19 Oct 2015, Xusangdi wrote: > > > > > > > > > -----Original Message----- > > > > > From: ceph-devel-owner@xxxxxxxxxxxxxxx > > > > > [mailto:ceph-devel-owner@xxxxxxxxxxxxxxx] On Behalf Of Chen, > > > > > Xiaoxi > > > > > Sent: Monday, October 19, 2015 9:11 AM > > > > > To: xusangdi 11976 (RD) > > > > > Cc: ceph-devel@xxxxxxxxxxxxxxx > > > > > Subject: RE: chooseleaf may cause some unnecessary pg migrations > > > > > > > > > > Sorry but not following... > > > > > > > > > > > then shut down one or more osds (please don't touch the > > > > > > crushmap, just stop the osd service or kill > > > > > its process). > > > > > > > > > > In this case, OSD is only down but not out, but will be marked > > > > > out after > > > 300s. > > > > > > > > > > So in what case your patch is helping? > > > > > > > > > > If you said your patch helps on "down and out" , then my > > > > > experiment is exactly the case, > > > > > > > > > > > > > I am afraid it is probably not. Could you tell me how did you > > > > simulate the osd "down and out" situation using crushtool? If it > > > > was done by arguments such as '--remove-item' or 'reweight-item', > > > > it modified the crushmap and is not what I'm aiming for. > > > > > > There is a --weight argument (noted in usage near --test, which is > > > the only piece that uses it). The crush map is not modified--only > > > the weight vector that is passed in when a mapping is calculated > > > (which is the equivalent of the in/out state in Ceph's OSDMap). This > should let you simulate this case. > > > > > > When I'm debugging/understanding these issues I usually change the > > > dprintk #define at the top of crush/mapper.c and use crushtool or > > > osdmaptool to calculate a single mapping, comparing the log before > > > and after a particular change. > > > > > > sage > ---------------------------------------------------------------------------------------------- > --------------------------------------- > 本邮件及其附件含有杭州华三通信技术有限公司的保密信息，仅限于发 > 送给上面地址中列出 > 的个人或群组。禁止任何其他人以任何形式使用（包括但不限于全部或 > 部分地泄露、复制、 > 或散发）本邮件中的信息。如果您错收了本邮件，请您立即电话或邮件 > 通知发件人并删除本 > 邮件！ > This e-mail and its attachments contain confidential information from H3C, > which is intended only for the person or entity whose address is listed above. > Any use of the information contained herein in any way (including, but not > limited to, total or partial disclosure, reproduction, or dissemination) by > persons other than the intended > recipient(s) is prohibited. If you receive this e-mail in error, please notify the > sender by phone or email immediately and delete it! ��.n��������+%������w��{.n����z��u���ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
