Paul Emmerich wrote: > +1 on adding them all at the same time. > > All these methods that gradually increase the weight aren't really > necessary in newer releases of Ceph.
Because the default backfill/recovery values are lower than they were in, say, Dumpling? Doubling (or more) the size of a cluster in one swoop still means a lot of peering and a lot of recovery I/O, I’ve seen a cluster’s data rate go to or near 0 for a brief but nonzero length of time. If something goes wrong with the network (cough cough subtle jumbo frame lossage cough) , if one has fat-fingered something along the way, etc. going in increments means that a ^C lets the cluster stablize before very long. Then you get to troubleshoot with HEALTH_OK instead of HEALTH_WARN or HEALTH_ERR. Having experienced a cluster be DoS’d for hours when its size was tripled in one go, I’m once bitten twice shy. Yes, that was Dumpling, but even with SSDs on Jewel and Luminous I’ve seen sigificant client performance impact from en-masse topology changes. — aad _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
