Hi Dan, Speaking for myself, it could definitely be useful.
Kr, Wannes ________________________________ From: Dan van der Ster via ceph-users <[email protected]> Sent: Tuesday, April 28, 2026 02:59 To: Iztok Gregori <[email protected]> Cc: [email protected] <[email protected]> Subject: [ceph-users] Re: Best "modern" approach to drain/fill a OSD server Hello! I'm glad to see that this info is still proving useful to the community. Here's a pretty comprehensive document explaining the typical upmap-remapped workflow: https: //urldefense. com/v3/__https: //docs. clyso. com/docs/kb/rados/adding-hosts-osds/__;!!FtrhtPsWDhZ6tw!EYA3GHD_cjvUgVuwVS1tqn71YZ0peFcj2lpFMCLJHnptXIVYM9BIQSIAsnUxfEjRbdIYZwvr9YnzWNqA$[docs[. ]clyso[. ]com] ZjQcmQRYFpfptBannerStart This Message Is From an External Sender This message came from outside your organization. ZjQcmQRYFpfptBannerEnd Hello! I'm glad to see that this info is still proving useful to the community. Here's a pretty comprehensive document explaining the typical upmap-remapped workflow: https://urldefense.com/v3/__https://docs.clyso.com/docs/kb/rados/adding-hosts-osds/__;!!FtrhtPsWDhZ6tw!EYA3GHD_cjvUgVuwVS1tqn71YZ0peFcj2lpFMCLJHnptXIVYM9BIQSIAsnUxfEjRbdIYZwvr9YnzWNqA$[docs[.]clyso[.]com] If it can be useful, I'm thinking of organizing an OSD balancing happy hour call in the next month or so. Maybe mid-May or so on a Friday afternoon (EU time) / morning (US time). Thanks! Dan -- Dan van der Ster Ceph Executive Council | CTO @ CLYSO Try our Ceph Analyzer -- https://urldefense.com/v3/__https://analyzer.clyso.com/__;!!FtrhtPsWDhZ6tw!EYA3GHD_cjvUgVuwVS1tqn71YZ0peFcj2lpFMCLJHnptXIVYM9BIQSIAsnUxfEjRbdIYZwvr9SYJizdm$[analyzer[.]clyso[.]com] https://urldefense.com/v3/__https://clyso.com__;!!FtrhtPsWDhZ6tw!EYA3GHD_cjvUgVuwVS1tqn71YZ0peFcj2lpFMCLJHnptXIVYM9BIQSIAsnUxfEjRbdIYZwvr9fxIWf2M$[clyso[.]com] | [email protected] On Mon, Apr 27, 2026 at 7:11 PM Iztok Gregori via ceph-users <[email protected]> wrote: > > Hi to all! > > I'm searching the wisdom of the community on how to drain/fill an OSD > server (like for removal, bulk disk replacing, filestore to bluestore > conversion...) without impacting on the performance of the cluster. > > We are using the 'ceph-gentle-reweight' script, which is running fine, > but we are interested to know if there is a newer approach for this job. > > Searching the web I found a pdf of the talk of Dan van der Ster about > "Mastering Ceph Operations" (NYC Ceph Day 2024) in which he talks about > using the 'balancer' in 'upmap' mode (and a "magic" script) to move the > PGs from/to the OSDs in the background. > > So the balancer upmap approach can be used to drain a node following > this procedure: > - set balancer tunables (like 'target_max_misplaced_ratio') > - activate the balancer in upmap mode (if not already active) > - 'ceph osd crush reweight-subtree' to 0.1 for the host we wish to drain > - run the magic script 'upmap-remapped.py' > - 'ceph osd crush reweight-subtree' to 0 for the host we wish to drain > - do stuff on the node (remove, reinstall etc etc). > > But what is the implication for the whole cluster, how this background > job affects its performance? > > I assume that 'target_max_misplaced_ratio' is a key parameter to avoid > large data movement in a given time, there is more to look into? > > And there are other approaches for the job? > > Thanks a lot! > Iztok > > _______________________________________________ > ceph-users mailing list -- [email protected] > To unsubscribe send an email to [email protected] _______________________________________________ ceph-users mailing list -- [email protected] To unsubscribe send an email to [email protected] _______________________________________________ ceph-users mailing list -- [email protected] To unsubscribe send an email to [email protected]
