You can adjust the Primary Affinity down on the larger drives so they’ll get less read load. In one test I’ve seen this result in a 10-15% increase in read throughout but it depends on your situation.
Optimal settings would require calculations that make my head hurt, maybe someone has a tool but I haven’t seen it. You might want to ensure that the drives are spread evenly across your (unspecified) failure domains so that the extra capacity isn’t wasted, again depending on your topology. > On Mar 31, 2020, at 8:49 AM, Eneko Lacunza <elacu...@binovo.es> wrote: > > Hi Andras, > >> El 31/3/20 a las 16:42, Andras Pataki escribió: >> I'm looking for some advice on what to do about drives of different sizes in >> the same cluster. >> >> We have so far kept the drive sizes consistent on our main ceph cluster >> (using 8TB drives). We're getting some new hardware with larger, 12TB >> drives next, and I'm pondering on how best to configure them. If I just >> simply add them, they will have 1.5x the data (which is less of a problem), >> but will also get 1.5x the iops - so I presume it will slow the whole >> cluster down as a result (these drives will be busy, and the rest will not >> be as much). I'm wondering how people generally handle this. >> >> I'm more concerned about these larger drives being busier than the rest - so >> I'd like to be able to put for example 1/3 drive of less accessed data on >> them in addition to the usual data - to use the extra capacity but not >> increase the load on them. Is there an easy way to accomplish this? One >> possibility is to run two OSDs on the drive (in two crush hierarchies), >> which isn't ideal. Can I just run one OSD somehow and put it into two crush >> roots, or something similar? > You should adjust the weight of the new 12TB disk OSDs, to match the weight > of the current 8TB OSDs. > > That will make the new disks the same as the old disks to Ceph :-) But you'll > lost the extra 4TB space, until you remove the 8TB disks from the cluster... > > Cheers > Eneko > > -- > Zuzendari Teknikoa / Director Técnico > Binovo IT Human Project, S.L. > Telf. 943569206 > Astigarragako bidea 2, 2º izq. oficina 11; 20180 Oiartzun (Gipuzkoa) > www.binovo.es > _______________________________________________ > ceph-users mailing list -- ceph-users@ceph.io > To unsubscribe send an email to ceph-users-le...@ceph.io _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-le...@ceph.io
