There's probably a middle ground where you get the best of both worlds. Maybe 2-4 OSD's per compute node alongside dedicated Ceph nodes. That way you get a bit of extra storage and can still use lower end CPU's, but don't have to worry so much about resource contention. > -----Original Message----- > From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On Behalf Of > Martin Millnert > Sent: 29 March 2015 19:58 > To: Mark Nelson > Cc: ceph-users@xxxxxxxxxxxxxx > Subject: Re: running Qemu / Hypervisor AND Ceph on the same > nodes > > On Thu, Mar 26, 2015 at 12:36:53PM -0500, Mark Nelson wrote: > > Having said that, small nodes are > > absolutely more expensive per OSD as far as raw hardware and > > power/cooling goes. > > The smaller volume manufacturers have on the units, the worse the margin > typically (from buyers side). Also, CPUs typically run up a premium the higher > you go. I've found a lot of local maximas, optimization-wise, over the past > years both in 12 OSD/U vs 18 OSD/U dedicated storage node setups, for > instance. > There may be local maximas along colocated low-scale storage/compute > nodes, but the one major problem with colocating storage with compute is > that you can't scale compute independently from storage efficiently, on > using that building block alone. There may be temporal optimizations in > doing so however (e.g. before you have reached sufficient scale). > > There's no single optimal answer when you're dealing with 20+ variables to > consider... :) > > BR, > Martin _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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