On Thu, 01 Jan 2015 13:59:57 +1000 Lindsay Mathieson wrote: > As mentioned before :) we have two osd ndoes with one 3TB osd each. > (replica 2) > > About to add a smaller (1TB) faster drive to each node > > From the docs, normal practice would be to weight it in accordance with > size, i.e 3 for the 3TB OSD, 1 for the 1TB OSD. > > But I'd like to spread it 50/50 to take better advantage of the faster > drive, so weight them all at 1. Bad idea? > Other than the wasted space, no. It should achieve what you want. > We only have 1TB of data so I'm presuming the 1TB drives would get 500GB > each. > Expect a good deal of variance, Ceph still isn't very good at evenly distributing data (PGs actually): --- Filesystem 1K-blocks Used Available Use% Mounted on /dev/sdi1 2112738204 211304052 1794043640 11% /var/lib/ceph/osd/ceph-19 /dev/sdk1 2112738204 140998368 1864349324 8% /var/lib/ceph/osd/ceph-21 --- On OSD 19 are 157 PGs, on 21 just 105, perfectly explaining this size difference of about 33%. That's on a Firefly cluster with 24 OSDs and more than adequate number of PGs per OSD (128). Christian -- Christian Balzer Network/Systems Engineer chibi@xxxxxxx Global OnLine Japan/Fusion Communications http://www.gol.com/ _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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