On Wed, Apr 17, 2013 at 3:02 PM, Steve Barber <steve.barber@xxxxxxxx> wrote: > 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 believe there are some people running with this architecture; there's just less knowledge about how it behaves in the long term. It should be fine subject to the standard issues with RAID5/6 small writes, which OSDs do a lot of (and I don't know why you'd bother using a mirroring RAID instead of Ceph replication!). I can say that there would be little point to carving up the arrays into multiple OSDs; other than that, have fun. :) -Greg Software Engineer #42 @ http://inktank.com | http://ceph.com > > 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 -- 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
