Den ons 9 okt. 2024 kl 20:48 skrev Frank Schilder <frans@xxxxxx>: > 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@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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