With sufficiently new CRUSH versions (all the latest point releases on LTS?) I think you can simply have the rule return extra IDs which are dropped if they exceed the number required. So you can choose two chassis, then have those both choose to lead OSDs, and return those 4 from the rule. -Greg On Fri, Feb 13, 2015 at 6:13 AM Luke Kao <luke....@mycom-osi.com> wrote:
> Dear cepher, > > Currently I am working on crushmap to try to make sure the at least one > copy are going to different chassis. > > Say chassis1 has host1,host2,host3, and chassis2 has host4,host5,host6. > > > > With replication =2, it’s not a problem, I can use the following step in > rule > > step take chasses1 > > step chooseleaf firstn 1 type host > > step emit > > step take chasses2 > > step chooseleaf firstn 1 type host > > step emit > > > > But for replication=3, I tried > > step take chasses1 > > step chooseleaf firstn 1 type host > > step emit > > step take chasses2 > > step chooseleaf firstn 1 type host > > step emit > > step take default > > step chooseleaf firstn 1 type host > > step emit > > > > At the end, the 3rd osd returned in rule test is always duplicate with > first 1 or first 2. > > > > Any idea or what’s the direction to move forward? > > Thanks in advance > > > > BR, > > Luke > > MYCOM-OSI > > > > ------------------------------ > > This electronic message contains information from Mycom which may be > privileged or confidential. The information is intended to be for the use > of the individual(s) or entity named above. If you are not the intended > recipient, be aware that any disclosure, copying, distribution or any other > use of the contents of this information is prohibited. If you have received > this electronic message in error, please notify us by post or telephone (to > the numbers or correspondence address above) or by email (at the email > address above) immediately. > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >
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