Den ons 18 aug. 2021 kl 21:49 skrev Francesco Piraneo G. <fpiraneo@xxxxxxxxxxx>: > > Il 17.08.21 16:34, Marc ha scritto: > > > ceph-volume lvm zap --destroy /dev/sdb > > ceph-volume lvm create --data /dev/sdb --dmcrypt > > > > systemctl enable ceph-osd@0 > > > Hi Marc, > > it worked! Thank you very much! > > I have some question: > > 1. ceph-volume already enable and run ceph-osd, so I'm not required to > run systemctl enable , is this correct? Correct. > 2. I know there is also the possibility to define two different > partitions on OSD for journal and data, properly sizing the journal > partition taking account of device throughput; in our case how is sized > the journal? It's on the same partition (I suppose inspecting the device > with lsblk)? There is a significant performance gain manually sizing the > journal and putting it on different device partition? If your kernel is old (especially like 2.6.x when we started with ceph) having more separate devices (ie, partitions) seemed to allow SSD and NVME to send more IO to the drive, but I think the more recent your kernel is, the better it handles such things now, so the gains might not be as big as they used to be. Also, sizing correctly can be hard, and if too small, it spills over to the data device anyhow, so I think it mostly evens out. > 3. As I read on RedHat doc for production clusters they suggest to > introduce new OSD with a prepare/activate instead of a one-shot OSD > creation "avoiding large amounts of data being rebalanced"; in your > opinion it's possible a gradual OSD integration on a running cluster of > several OSD taking a look at when the rebalancing operation end? You can set the ceph.conf [osd] section so that new devices get an initial crush weight of 0.001 or something really small but non-zero, then it joins the cluster but doesn't get any large amounts of data or often no data at all. After all new OSDs are in and up, you can slowly increase the crush weights to what they should actually be for the size of the drive at your own pace. -- May the most significant bit of your life be positive. _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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