how ceph RBD data placement works

asked 2017-03-13 09:58:01 -0600

Damian Dąbrowski gravatar image

Hello,

I'm trying to understand how ceph RBD stores data. I wrote example scenario, can someone confirm that i think well? I would be very grateful.

So:

I create VM disk - RBD image in pool X(3 replicas, 90 PGs). This block device is divided into small objects(for ex. 4mb each). Each of this objects is assigned pseudo-randomly to one of 90 PGs(by CRUSH algorithm?) and then its replicated over 3 OSDs belonging to this PG.

Am i right?

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