Add to the info, I have a slightly modified rule to take advantage of the new storage class. rule ssd-hybrid { id 2 type replicated min_size 1 max_size 10 step take default class ssd step chooseleaf firstn 1 type host step emit step take default class hdd step chooseleaf firstn -1 type host step emit } Regards, Horace Ng ----- Original Message ----- From: "horace" <horace@xxxxxxxxx> To: "ceph-users" <ceph-users@xxxxxxxxxxxxxx> Sent: Wednesday, May 23, 2018 3:56:20 PM Subject: SSD-primary crush rule doesn't work as intended I've set up the rule according to the doc, but some of the PGs are still being assigned to the same host. http://docs.ceph.com/docs/master/rados/operations/crush-map-edits/ rule ssd-primary { ruleset 5 type replicated min_size 5 max_size 10 step take ssd step chooseleaf firstn 1 type host step emit step take platter step chooseleaf firstn -1 type host step emit } Crush tree: [root@ceph0 ~]# ceph osd crush tree ID CLASS WEIGHT TYPE NAME -1 58.63989 root default -2 19.55095 host ceph0 0 hdd 2.73000 osd.0 1 hdd 2.73000 osd.1 2 hdd 2.73000 osd.2 3 hdd 2.73000 osd.3 12 hdd 4.54999 osd.12 15 hdd 3.71999 osd.15 18 ssd 0.20000 osd.18 19 ssd 0.16100 osd.19 -3 19.55095 host ceph1 4 hdd 2.73000 osd.4 5 hdd 2.73000 osd.5 6 hdd 2.73000 osd.6 7 hdd 2.73000 osd.7 13 hdd 4.54999 osd.13 16 hdd 3.71999 osd.16 20 ssd 0.16100 osd.20 21 ssd 0.20000 osd.21 -4 19.53799 host ceph2 8 hdd 2.73000 osd.8 9 hdd 2.73000 osd.9 10 hdd 2.73000 osd.10 11 hdd 2.73000 osd.11 14 hdd 3.71999 osd.14 17 hdd 4.54999 osd.17 22 ssd 0.18700 osd.22 23 ssd 0.16100 osd.23 #ceph pg ls-by-pool ssd-hybrid 27.8 1051 0 0 0 0 4399733760 1581 1581 active+clean 2018-05-23 06:20:56.088216 27957'185553 27959:368828 [23,1,11] 23 [23,1,11] 23 27953'182582 2018-05-23 06:20:56.088172 27843'162478 2018-05-20 18:28:20.118632 With osd.23 and osd.11 being assigned on the same host. Regards, Horace Ng _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com