Well, as stated in the other email I think in the EC scenario you can set size=k+m for the pgcalc tool. If you want 10+2 then in theory you should be able to get away with 6 nodes to survive a single node failure if you can guarantee that every node will always receive 2 out of the 12 chunks - looks like this might be achievable: http://ceph.com/planet/erasure-code-on-small-clusters/
On Mon, Nov 13, 2017 at 1:32 PM, Tim Gipson <tgip...@ena.com> wrote: > I guess my questions are more centered around k+m and PG calculations. > > As we were starting to build and test our EC pools with our infrastructure we > were trying to figure out what our calculations needed to be starting with 3 > OSD hosts with 12 x 10 TB OSDs a piece. The nodes have the ability to expand > to 24 drives a piece and we hope to eventually get to around a 1PB cluster > after we add some more hosts. Initially we hoped to be able to do a k=10 m=2 > on the pool but I am not sure that is going to be feasible. We’d like to set > up the failure domain so that we would be able to lose an entire host without > losing the cluster. At this point I’m not sure that’s possible without > bringing in more hosts. > > Thanks for the help! > > Tim Gipson > > > On 11/12/17, 5:14 PM, "Christian Wuerdig" <christian.wuer...@gmail.com> wrote: > > I might be wrong, but from memory I think you can use > http://ceph.com/pgcalc/ and use k+m for the size > > On Sun, Nov 12, 2017 at 5:41 AM, Ashley Merrick <ash...@amerrick.co.uk> > wrote: > > Hello, > > > > Are you having any issues with getting the pool working or just around > the > > PG num you should use? > > > > ,Ashley > > > > Get Outlook for Android > > > > ________________________________ > > From: ceph-users <ceph-users-boun...@lists.ceph.com> on behalf of Tim > Gipson > > <tgip...@ena.com> > > Sent: Saturday, November 11, 2017 5:38:02 AM > > To: ceph-users@lists.ceph.com > > Subject: [ceph-users] Erasure Coding Pools and PG calculation - > > documentation > > > > Hey all, > > > > I’m having some trouble setting up a Pool for Erasure Coding. I haven’t > > found much documentation around the PG calculation for an Erasure Coding > > pool. It seems from what I’ve tried so far that the math needed to set > one > > up is different than the math you use to calculate PGs for a regular > > replicated pool. > > > > Does anyone have any experience setting up a pool this way and can you > give > > me some help or direction, or point me toward some documentation that > goes > > over the math behind this sort of pool setup? > > > > Any help would be greatly appreciated! > > > > Thanks, > > > > > > Tim Gipson > > Systems Engineer > > > > > > _______________________________________________ > > ceph-users mailing list > > ceph-users@lists.ceph.com > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > > _______________________________________________ > > ceph-users mailing list > > ceph-users@lists.ceph.com > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > > _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
