Yes, RBD volumes are typically much larger than bluestore_min_alloc_size. Typically your client filesystem is built *within* an RBD volume, but to Ceph it’s a single, monolithic image. > On Sep 14, 2021, at 7:27 AM, Sebastien Feminier <sebastien.feminier@xxxxxxxxxxxxxxx> wrote: > > > thanks josh , my cluster is octopus on hdd (for testing) ,so i have to re-create OSDs and change bluestore_min_alloc_size before creating OSDs ? > Is this normal that my rbd pool does not having size amplification ? > >> Hey Seb, >> >>> I have a test cluster on which I created pools rbd and cephfs (octopus), when >>> I copy a directory containing many small files on a pool rbd the USED part of >>> the ceph df command seems normal on the other hand on cephfs the USED part >>> seems really abnormal, I tried to change the blocksize >>> bluestore_min_alloc_size but it didn't change anything, would the solution be >>> to re-create the pool or outright the OSDs? >> >> bluestore_min_alloc_size has an effect only at OSD creation time; if >> you changed it after creating the OSDs, it will have had no effect >> yet. If your pool is on HDDs and this is pre-Pacific, then the default >> of 64k will have a huge amplification effect for small objects. >> >> Josh > _______________________________________________ > ceph-users mailing list -- ceph-users@xxxxxxx > To unsubscribe send an email to ceph-users-leave@xxxxxxx _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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