I have a newly created cluster with 68 osds and the default of 2 replicas. The default pools are created with 64 placement groups . The documentation in http://ceph.com/docs/master/rados/operations/pools/ states for osd pool creation : "We recommend approximately 50-100 placement groups per OSD to balance out memory and CPU requirements and per-OSD load. For a single pool of objects, you can use the following formula: Total PGS = (osds *100)/Replicas"
For this cluster pools should have 3200 pgs [ (64*100)/2] according to the recommendation. Why isn't the guideline followed for default pools? Maybe they're created prior to having all the osds activated? Maybe I'm reading the documentation incorrectly. /home/ceph/bin# ceph osd getmaxosd max_osd = 68 in epoch 219 /home/ceph/bin# ceph osd getmaxosd max_osd = 68 in epoch 219 /home/ceph/bin# ceph osd lspools 0 data,1 metadata,2 rbd, /home/ceph/bin# ceph osd pool get data pg_num pg_num: 64 /home/ceph/bin# ceph osd pool get data size size: 2 Thanks, Tim _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
