Am 19.07.2018 um 05:57 schrieb Konstantin Shalygin: >> Now my first question is: >> 1) Is there a way to specify "take default class (ssd or nvme)"? >> Then we could just do this for the migration period, and at some point >> remove "ssd". >> >> If multi-device-class in a crush rule is not supported yet, the only >> workaround which comes to my mind right now is to issue: >> $ ceph osd crush set-device-class nvme <old_ssd_osd> >> for all our old SSD-backed osds, and modify the crush rule to refer to class >> "nvme" straightaway. > > > My advice is to set class to 'nvme' to your current osd's with class 'ssd' > and change crush rule to this class. > > You still have to do it, better sooner than later.Either use the ssd class > for your future drives, in case when you switch all your ssd to nvme and > forgot about ssd disks.
Yes, this sounds good. I'll schedule this for as soon as we have a small I/O pause in any case, just to be sure this will not interfere with ongoing I/O. Changing the old devices and the crush rule sounds like the best plan, then all future NVMEs will be handled correctly without any manual intervention. > > >> Here my third question: >> 3) Are the tunables used for NVME devices the same as for SSD devices? >> I do not find any NVME tunables here: >> http://docs.ceph.com/docs/master/rados/configuration/osd-config-ref/ >> Only SSD, HDD and Hybrid are shown. > > Ceph is doesn't care about nvme/ssd. Ceph is only care is_rotational drive or > not. > > > "bluefs_db_rotational": "0", > "bluefs_slow_rotational": "1", > "bluefs_wal_rotational": "0", > "bluestore_bdev_rotational": "1", > "journal_rotational": "0", > "rotational": "1" > Ah, I see! So those tunables (osd recovery sleep ssd, osd recovery sleep hdd, osd recovery sleep hybrid, and the other sleep parameters) just have a misleading name ;-). Thanks and all the best, Oliver > > > k >
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