Yes, there should a separate partition per OSD. You are probably looking at 10-20GB journal partition per OSD. If you are creating your cluster using ceph-deploy it can create journal partitions for you.
"The expected throughput number should include the expected disk throughput (i.e., sustained data transfer rate), and network throughput. For example, a 7200 RPM disk will likely have approximately 100 MB/s. Taking the min() of the disk and network throughput should provide a reasonable expected throughput. Some users just start off with a 10GB journal size". For example: osd journal size = 10000 On Wed, Aug 5, 2015 at 4:48 PM, Dominik Zalewski <dzalew...@optlink.co.uk> wrote: > Yes, there should a separate partition per OSD. You are probably looking > at 10-20GB journal partition per OSD. If you are creating your cluster > using ceph-deploy it can create journal partitions for you. > > "The expected throughput number should include the expected disk > throughput (i.e., sustained data transfer rate), and network throughput. > For example, a 7200 RPM disk will likely have approximately 100 MB/s. > Taking the min() of the disk and network throughput should provide a > reasonable expected throughput. Some users just start off with a 10GB > journal size". For example: > > osd journal size = 10000 > > > On Wed, Aug 5, 2015 at 4:38 PM, SUNDAY A. OLUTAYO <olut...@sadeeb.com> > wrote: > >> I intend to have 5-8 OSDs for 400GB SSD. >> >> Should there be different partitions for each OSD on the SSD? >> >> >> Thanks, >> >> Sunday Olutayo >> >> >> ------------------------------ >> *From: *"Dominik Zalewski" <dzalew...@optlink.co.uk> >> *To: *"SUNDAY A. OLUTAYO" <olut...@sadeeb.com>, "ceph-users" < >> ceph-users@lists.ceph.com> >> *Sent: *Wednesday, August 5, 2015 3:38:20 PM >> *Subject: *Re: [ceph-users] Ceph Design >> >> >> I would suggest splitting OSDs across two or more SSD journals (depending >> on OSD write speed and SSD sustained speed limits) >> >> e.g 2x Intel S3700 400GB for 8-10 OSDs or 4x Intel S3500 300GB for 8-10 >> OSDs (it may vary depending on the setup) >> >> If you RAID-1 SSD journals they will potentially "wear out" in the same >> time due to writes happening on both of them. >> >> You only going to get journal write performance penalty with RAID-1. >> >> Dominik >> >> >> On Wed, Aug 5, 2015 at 3:37 PM, Dominik Zalewski <dzalew...@optlink.co.uk >> > wrote: >> >>> I would suggest splitting OSDs across two or more SSD journals >>> (depending on OSD write speed and SSD sustained speed limits) >>> >>> e.g 2x Intel S3700 400GB for 8-10 OSDs or 4x Intel S3500 300GB for 8-10 >>> OSDs (it may vary depending on the setup) >>> >>> If you RAID-1 SSD journals they will potentially "wear out" in the same >>> time due to writes happening on both of them. >>> >>> You only going to get journal write performance penalty with RAID-1. >>> >>> Dominik >>> >>> On Tue, Aug 4, 2015 at 10:54 PM, SUNDAY A. OLUTAYO <olut...@sadeeb.com> >>> wrote: >>> >>>> I am thinking of having ceph journal on a RAID1 SSD. >>>> >>>> Kindly advise me on this, does the RAID1 SSD for journal make sense? >>>> >>>> _______________________________________________ >>>> ceph-users mailing list >>>> ceph-users@lists.ceph.com >>>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >>>> >>>> >>> >> >> >
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