Re: Comparison of 3 replication models on Pech OSD cluster

Why object data mutations (write IOs to an object) can't be tracked using old-school bitmap?

That's what I call "write intent journaling" %) it's still a sort of "journaling" because you first modify the bitmap, fsync it, then proceed with the write itself. Ceph/Pech architecture, however, dictates that an RBD spans multiple OSDs. Because if it doesn't it stops being Ceph and becomes Linstor. :) and there is a Linstor already. :) in this case it seems that a journal is more convenient than a plain bitmap... aaand this is precisely what PGlog is (pglog isn't a journal with data, it only contains a list of updated objects). -- With best regards, Vitaliy Filippov