Re:HGST gets closer to shipping 10TB HDD
by ghshephard on Friday March 13, 2015 @03:18PM
(#9199349)
What's the sweet spot for Ceph cluster redundancy - Original + 3 Copies? I realize the answer is, "It depends on how much redundancy you want" - but I'm guessing that there is a general best practice that Ceph administrators have adopted?
Re:HGST gets closer to shipping 10TB HDD
by epistasis on Saturday March 14, 2015 @01:00PM
(#9203272)
Ceph is a Consistent and Partition tolerant system in the CAP formulation, at the expense of Availability. Fortunately for my use cases I've not needed high availability, which would require two separate clusters and replication between them.
I've mostly seen people use triplicate pools. For semi-warm storage I've been testing erasure coded pools, with a triplicate cache tier on top, and had good experiences on my test cluster.
And yes, in the clusters I've built I've always calculated what the chances are that X simultaneous drive failures will take out any data, and it's always been astronomically low.