Dear Ceph experts, recently we have upgraded our ceph cluster from octopus (15.2.17) to pacific (16.2.14 and then to 16.2.15). Just after upgrade warnings that all (except device_health_metrics pool) our pools have too many placement groups appeared. This warning looks like generated by autoscaler, but there was no suggestions from it. When I started to investigate situation, I turned bulk flag to true for pools intended to store large amount of data (just to look changes). After that most pools reports that they have too few placement groups, but there is still no suggestions from autoscaler (NEW PG_NUM column is empty) # ceph osd pool autoscale-status POOL SIZE TARGET SIZE RATE RAW CAPACITY RATIO TARGET RATIO EFFECTIVE RATIO BIAS PG_NUM NEW PG_NUM AUTOSCALE BULK metadata 22567M 3.0 57255G 0.0012 1.0 32 warn False rbd_hdd02_ec_meta 20817k 3.0 365.3T 0.0000 1.0 32 warn False device_health_metrics 1002M 3.0 205.4T 0.0000 1.0 1 on False rbd_ssd_ec_meta 0 3.0 57255G 0.0000 1.0 32 warn False cmd_spool 45094G 1.3333333730697632 205.4T 0.2859 1.0 512 warn True data 60496G 3.0 365.3T 0.4851 1.0 512 warn True rbd 2625G 3.0 205.4T 0.0374 1.0 64 warn True kedr_spool 6900G 10240G 1.3333333730697632 205.4T 0.0649 1.0 128 warn True gcf_spool 1119M 1.3333333730697632 205.4T 0.0000 1.0 32 warn True rbd_ssd 107.8G 3.0 57255G 0.0056 1.0 32 warn True data_ssd 775.8G 3.0 57255G 0.0407 1.0 128 warn True only warnings in 'ceph status' and 'ceph health detail' # ceph health detail HEALTH_WARN 6 pools have too few placement groups; 4 pools have too many placement groups [WRN] POOL_TOO_FEW_PGS: 6 pools have too few placement groups Pool data has 512 placement groups, should have 2048 Pool rbd has 64 placement groups, should have 512 Pool kedr_spool has 128 placement groups, should have 256 Pool gcf_spool has 32 placement groups, should have 256 Pool rbd_ssd has 32 placement groups, should have 2048 Pool data_ssd has 128 placement groups, should have 2048 [WRN] POOL_TOO_MANY_PGS: 4 pools have too many placement groups Pool metadata has 32 placement groups, should have 32 Pool rbd_hdd02_ec_meta has 32 placement groups, should have 32 Pool rbd_ssd_ec_meta has 32 placement groups, should have 32 Pool cmd_spool has 512 placement groups, should have 512 When I changed number of placement groups of pool kedr_spool from 128 to 256 as suggested in warning, data rebalanced successfully, but now pool warns that it have too many placement groups: Pool kedr_spool has 256 placement groups, should have 256. The most strange for me in these warnings is that the current number of PGs is the same that should be. What is it and what how to solve these warnings? Best regards, Dmitriy