Salut, The general recommended ratio (for me at least) is 3 journals per SSD. Using 200GB Intel DC S3700 is great. If you’re going with a low perf scenario I don’t think you should bother buying SSD, just remove them from the picture and do 12 SATA 7.2K 4TB. For medium and medium ++ perf using a ratio 1:11 is way to high, the SSD will definitely be the bottleneck here. Please also note that (bandwidth wise) with 22 drives you’re already hitting the theoretical limit of a 10Gbps network. (~50MB/s * 22 ~= 1.1Gbps). You can theoretically up that value with LACP (depending on the xmit_hash_policy you’re using of course). Btw what’s the network? (since I’m only assuming here). > On 15 Dec 2014, at 20:44, Florent MONTHEL <fmonthel@xxxxxxxxxxxxx> wrote: > > Hi, > > I’m buying several servers to test CEPH and I would like to configure journal on SSD drives (maybe it’s not necessary for all use cases) > Could you help me to identify number of SSD I need (SSD are very expensive and GB price business case killer… ) ? I don’t want to experience SSD bottleneck (some abacus ?). > I think I will be with below CONF 2 & 3 > > > CONF 1 DELL 730XC "Low Perf": > 10 SATA 7.2K 3.5 4TB + 2 SSD 2.5 » 200GB "intensive write" > > CONF 2 DELL 730XC « Medium Perf" : > 22 SATA 7.2K 2.5 1TB + 2 SSD 2.5 » 200GB "intensive write" > > CONF 3 DELL 730XC « Medium Perf ++" : > 22 SAS 10K 2.5 1TB + 2 SSD 2.5 » 200GB "intensive write" > > Thanks > > Florent Monthel > > > > > > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com Cheers. –––– Sébastien Han Cloud Architect "Always give 100%. Unless you're giving blood." Phone: +33 (0)1 49 70 99 72 Mail: sebastien.han@xxxxxxxxxxxx Address : 11 bis, rue Roquépine - 75008 Paris Web : www.enovance.com - Twitter : @enovance
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