Den ons 9 okt. 2024 kl 20:48 skrev Frank Schilder <fr...@dtu.dk>: > The PG count per OSD is a striking exception. Its just a number (well a range > with 100 recommended and 200 as a max: > https://docs.ceph.com/en/latest/rados/operations/pgcalc/#keyDL). It just is. > And this doesn't make any sense unless there is something really evil lurking > in the dark. > For comparison, a guidance that does make sense is something like 100PGs per > TB. That I would vaguely understand: to keep the average PG size constant at > a max of about 10G.
To be fair, this number could just be something vaguely related to "spin drives have 100-200 iops", and while cent/rhel linux kernels 10 years ago did have some issues in getting io done in parallel as much as possible towards a single device, doing multiple OSDs on flash devices would have been both a way to get around this limitation in the IO middle layer, and a way to "tell" ceph it can send more IO to the device since it has multiple OSDs on it. -- May the most significant bit of your life be positive. _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-le...@ceph.io
