A very interesting question and I would add the follow up question: Is there an easy way to add an external DB/WAL devices to an existing OSD? I suspect that it might be something on the lines of: - stop osd - create a link in ...ceph/osd/ceph-XX/block.db to the target device - (maybe run some kind of osd mkfs ?) - start osd Has anyone done this so far or recommendations on how to do it? Which also makes me wonder: what is actually the format of WAL and BlockDB in bluestore? Is there any documentation available about it? Best, Nico Caspar Smit <casparsmit@xxxxxxxxxxx> writes: > Hi All, > > What would be the proper way to preventively replace a DB/WAL SSD (when it > is nearing it's DWPD/TBW limit and not failed yet). > > It hosts DB partitions for 5 OSD's > > Maybe something like: > > 1) ceph osd reweight 0 the 5 OSD's > 2) let backfilling complete > 3) destroy/remove the 5 OSD's > 4) replace SSD > 5) create 5 new OSD's with seperate DB partition on new SSD > > When these 5 OSD's are big HDD's (8TB) a LOT of data has to be moved so i > thought maybe the following would work: > > 1) ceph osd set noout > 2) stop the 5 OSD's (systemctl stop) > 3) 'dd' the old SSD to a new SSD of same or bigger size > 4) remove the old SSD > 5) start the 5 OSD's (systemctl start) > 6) let backfilling/recovery complete (only delta data between OSD stop and > now) > 6) ceph osd unset noout > > Would this be a viable method to replace a DB SSD? Any udev/serial nr/uuid > stuff preventing this to work? > > Or is there another 'less hacky' way to replace a DB SSD without moving too > much data? > > Kind regards, > Caspar > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com -- Modern, affordable, Swiss Virtual Machines. Visit www.datacenterlight.ch _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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