Hi, this doesn't sound like a good idea: two hosts is usually a poor configuration for Ceph. Also, fewer disks on more servers is typically better than lots of disks in few servers.
But to answer your question: you could use a crush rule like this: min_size 4 max_size 4 step take default step choose firstn 2 type host step choose firstn 2 type osd step emit And then create a pool with 4/2 and assign this crush rule to it. See http://docs.ceph.com/docs/jewel/rados/operations/crush-map/ Paul 2018-04-23 17:17 GMT+02:00 Christopher Meadors < christopher.mead...@twrcommunications.com>: > I'm starting to get a small Ceph cluster running. I'm to the point where > I've created a pool, and stored some test data in it, but I'm having > trouble configuring the level of replication that I want. > > The goal is to have two OSD host nodes, each with 20 OSDs. The target > replication will be: > > osd_pool_default_size = 4 > osd_pool_default_min_size = 2 > > That is, I want two copies on each host, allowing for OSD failures or host > failures without data loss. > > How to best achieve this replication? Is this strictly a CRUSH map rule, > or can it be done with the cluster conf? Pointers or examples would be > greatly appreciated. > > Thanks! > > -- > Chris > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > -- -- Paul Emmerich Looking for help with your Ceph cluster? Contact us at https://croit.io croit GmbH Freseniusstr. 31h 81247 München www.croit.io Tel: +49 89 1896585 90
_______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
