>> There are two types of "object", RBD-image-object and 8MiB-block-object. >> When create a RBD image, a RBD-image-object is created and 12800 >> 8MiB-block-objects >> are allocated. That whole RBD-image-object is mapped to a single PG, which >> is mapped >> to 3 OSDs (replica 3). That means, all user data on that RBD image is stored >> in those >> 3 OSDs. Is my understanding correct? > > RBD image is not a object, is a bunch of objects as block device abstraction. > Nope, each object of image may be placed to pseudo random placement. For > example if you > have 10000 osds and 10GiB image with 4MiB objects your image may be placed to > 2560 > different PGs on 100-1000-2560 OSDs...
That's what I thought. I am confused by this. # ceph osd map vm fcb09c9c-4cd9-44d8-a20b-8961c6eedf8e_disk osdmap e18381 pool 'vm' (4) object 'fcb09c9c-4cd9-44d8-a20b-8961c6eedf8e_disk' -> pg 4.c7a78d40 (4.0) -> up ([4,17,6], p4) acting ([4,17,6], p4) It calls RBD image "object" and it shows the whole image maps to a single PG, while the image is actually split into many objects each of which maps to a PG. How am I supposed to understand the output of this command? Thanks! Tony _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-le...@ceph.io
