Hello, There are of course a number of threads in the ML archives about things like this.
On Sat, 24 Oct 2015 17:48:35 +0200 Mike Miller wrote: > Hi, > > as I am planning to set up a ceph cluster with 6 OSD nodes with 10 > harddisks in each node, could you please give me some advice about > hardware selection? CPU? RAM? > I am planning a 10 GBit/s public and a separate 10 GBit/s private > network. > If I read this correctly your OSDs are entirely HDD based (no journal SSDs). In that case you'll be lucky to see writes faster than 750MB/s, meaning your split network is wasted. IMHO a split cluster/public network only makes sense if you can actually saturate either link if not both. In your case a redundant (LACP) setup would be much more beneficial, unless your use case is vastly skewed to reads from hot (in page cache) objects. As for CPU, pure HDD OSDs will do well with about 1GHz per OSD, the more small write I/Os you have the more power you need. For OSDs with journal SSDs my rule of thumb is at least 2GHz, for purely SSD based OSDs whatever you can afford. 2GB RAM per OSD are generally sufficient, however more is definitely better in my book. This is especially true when you have hot (read) objects that may get evicted from local (in VM) page caches, but still fit comfortably in the distributed page caches of your OSD nodes. Regards, Christian > For a smaller test cluster with 5 OSD nodes and 4 harddisks each, 2 > GBit/s public and 4 GBit/s private network, I already tested this using > core i5 boxes 16GB RAM installed. In most of my test scenarios including > load, node failure, backfilling, etc. the CPU usage was not at all the > bottleneck with a maximum of about 25% load per core. The private > network was also far from being fully loaded. > > It would be really great to get some advice about hardware choices for > my newly planned setup. > > Thanks very much and regards, > > Mike > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > -- Christian Balzer Network/Systems Engineer ch...@gol.com Global OnLine Japan/Fusion Communications http://www.gol.com/ _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
