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 <elacunza@xxxxxxxxx> 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@xxxxxxx > To unsubscribe send an email to ceph-users-leave@xxxxxxx _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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