If you stop the OSDs cleanly then that should cause no disruption to clients. Starting the OSD back up is another story, expect slow request for a while there and unless you have lots of very fast CPUs on the OSD node, start them one-by-one and not all at once. Jan > On 13 Jul 2016, at 14:37, Wido den Hollander <wido@xxxxxxxx> wrote: > > >> Op 13 juli 2016 om 14:31 schreef Kees Meijs <kees@xxxxxxxx>: >> >> >> Hi Cephers, >> >> There's some physical maintainance I need to perform on an OSD node. >> Very likely the maintainance is going to take a while since it involves >> replacing components, so I would like to be well prepared. >> >> Unfortunately it is no option to add another OSD node or rebalance at >> this time, so I'm planning to operate in degraded state during the >> maintainance. >> >> If at all possible, I would to shut down the OSD node cleanly and >> prevent slow (or even blocking) requests on Ceph clients. >> >> Just setting the noout flag and shutting down the OSDs on the given node >> is not enough as it seems. In fact clients do not act that well in this >> case. Connections time out and for a while I/O seems to stall. >> > > noout doesn't do anything with the clients, it just tells the cluster not to mark any OSD as out after they go down. > > If you want to do this slowly, take the OSDs down one by one and wait for the PGs to become active+X again. > > When you start, do the same again, start them one by one. > > You will always have a short moment where the PGs are inactive. > >> Any thoughts on this, anyone? For example, is it a sensible idea and are >> writes still possible? Let's assume there are OSDs on to the >> to-be-maintained host which are primary for sure. >> >> Thanks in advance! >> >> Cheers, >> Kees >> >> >> _______________________________________________ >> ceph-users mailing list >> ceph-users@xxxxxxxxxxxxxx >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
 |