Hello, I would like to know the maximum number of node failures for a EC8+3 pool in a 12-node cluster with 3 OSDs in each node. The size and min_size of the EC8+3 pool is configured as 11 and 8, and OSDs of each PG are selected by host. When there is no node failure, the maximum number of node failures is 3, right? After unplugging a OSD (osd.14) in the cluster, I check the PG acting set changes and one of the results is shown as below: T0: [15,31,11,34,28,1,8,26,14,19,5] T1: after unplugging a OSD (osd.14) and recovery started [15,31,11,34,28,1,8,26,NONE,19,5] T2: [15,31,11,34,21,1,8,26,19,29,5] T3: [15,31,11,34,NONE,1,8,26,NONE,NONE,5] T4: recovery was done [15,31,11,34,21,1,8,26,19,29,5] For the PG, 3 OSD peers changed during the recovery progress ([_,_,_,_,28->21,_,_,_,14->19,19->29,_]). It seems that min_size (8) of chunks of the EC8+3 pool are kept during recovery. Does it mean that no more node failures are bearable during T3 to T4? Can we calculate the maximum number of node failures by examining all the acting sets of the PGs? Is there some simple way to obtain such information? Any ideas and feedback are appreciated, thanks! - Jerry _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
 |