On Wed, Apr 17, 2013 at 04:49:53PM -0400, Jeff Mitchell wrote in another thread: > ... If you > set up the OSDs such that each OSD is based off of a ZFS mirror, you > get these benefits locally. For some people, especially when heavy on > reads (due to the intelligent caching), a solution that knocks the > remote replication level down by one but uses local mirrors for OSDs > may provide good functionality and safety compromises. Funny that you mention this today; that's exactly an idea I was thinking about pursuing yesterday, so that I don't have to do repl=4 for data protection both between two sites and within each site (i.e. 2 copies of data at each site). If anybody is actively doing/trying this (whether via RAID or ZFS or whatever, although I'm particularly interested in a ZFS/ZoL solution) I'd love to see some discussion about it. In particular, has anyone tried making a big RAID set (of any type) and carving out space (logical volumes, zvols, etc.) to become virtual OSDs? Any architectural gotchas with this idea? I'm trying to set up a cluster spread across two server rooms in separate buildings that can survive an outage of one building and still have replicated (safe) data in the event of e.g. a disk failure during the outage. It seems like some local data protection would be much more efficient than having Ceph manage the extra replicas - subject to testing of course! As a side note I do like the thought of ZFS ensuring data integrity, and in the long run it might allow some of the same optimizations with Ceph that btrfs is used for now (re: snapshots, compression, etc.) and as Jeff mentioned, ZFS gives you a lot of performance tuning options. I'm thrilled to see that it's getting some attention. Steve -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
