I wouldn't advise upgrading yet if this cluster is going into production. I think several people got bitten last time round when they upgraded to pre hammer. Here is a good example on how to create separate root's for SSD's and HDD's http://ceph.com/docs/master/rados/operations/crush-map/#placing-different-pools-on-different-osds The rulesets then enable you to pin pools to certain crush roots. I highly recommend you use the "osd crush location hook =" config directive to use a script to auto place the OSD's on startup. Nick > -----Original Message----- > From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On Behalf Of > German Anders > Sent: 04 September 2015 17:18 > To: Nick Fisk <nick@xxxxxxxxxx> > Cc: ceph-users <ceph-users@xxxxxxxxxxxxxx> > Subject: Re: Best layout for SSD & SAS OSDs > > Thanks a lot Nick, regarding the power feeds, we only had two circuits for all > the racks, so I'll to do in the crush the "rack" bucket and separate the osd > servers on the rack buckets, then regarding the SSD pools, I've installed the > hammer version and wondering to upgrade to Infernalis v9.0.3 and apply the > SSD cache, or stay on Hammer and do the SSD pools and maybe left two > 800GB SSD for later used as Cache (1.6TB per OSD server), do you have a > crushmap example for this type of config? > Thanks a lot, > Best regards, > > > German > > 2015-09-04 13:10 GMT-03:00 Nick Fisk <nick@xxxxxxxxxx>: > Hi German, > > Are the power feeds completely separate (ie 4 feeds in total), or just each > rack has both feeds? If it’s the latter I don’t see any benefit from including > this into the crushmap and would just create a “rack” bucket. Also assuming > your servers have dual PSU’s, this also changes the power failure scenarios > quite a bit as well. > > In regards to the pools, unless you know your workload will easily fit into a > cache pool with room to spare, I would suggest not going down that route > currently. Performance in many cases can actually end up being worse if you > end up doing a lot of promotions. > > *However* I’ve been doing a bit of testing with the current master and > there are a lot of improvements around cache tiering that are starting to > have a massive improvement on performance. If you can get by with just the > SAS disks for now and make a more informed decision about the cache > tiering when Infernalis is released then that might be your best bet. > > Otherwise you might just be best using them as a basic SSD only Pool. > > Nick > > From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On Behalf Of > German Anders > Sent: 04 September 2015 16:30 > To: ceph-users <ceph-users@xxxxxxxxxxxxxx> > Subject: Best layout for SSD & SAS OSDs > > Hi cephers, > I've the following scheme: > 7x OSD servers with: > 4x 800GB SSD Intel DC S3510 (OSD-SSD) > 3x 120GB SSD Intel DC S3500 (Journals) > 5x 3TB SAS disks (OSD-SAS) > The OSD servers are located on two separate Racks with two power circuits > each. > I would like to know what is the best way to implement this.. use the 4x > 800GB SSD like a SSD-pool, or used them us a Cache pool? or any other > suggestion? Also any advice for the crush design? > Thanks in advance, > > > German > > _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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