On Tue, Dec 20, 2011 at 3:56 PM, Matt Weil <mweil@xxxxxxxxxxxxxxxx> wrote: > On 12/20/11 5:39 PM, Gregory Farnum wrote: >> >> On Tue, Dec 20, 2011 at 3:30 PM, Matt Weil<mweil@xxxxxxxxxxxxxxxx> wrote: >>> >>> Hello all: >>> >>> given six osd servers does it make any difference of each one also runs a >>> mds or not? >>> >>> How many mds's is to many. How does this effect metadata performance. >> >> Right now a single-MDS system is significantly more stable than a >> system with multiple active MDSes, so if possible you should use that >> configuration. Only add MDSes when you need more metadata throughput >> (probably you only need one). > > > Thanks for the response. > > these osd servers are also going run the client and serve out NFS. Make sure you carefully consider the deadlock risks associated with running filesystem clients and servers on the same machine... :) (See here:http://permalink.gmane.org/gmane.comp.file-systems.ceph.devel/4335 and the containing thread for more info if needed.) > Is it better to split the mds and mon out to a dedicated system? then run > standby on the active osd's Depends on your hardware and performance requirements — the MDS will consume as much RAM as you allow it to, and up to a CPU or so. The OSDs don't use much memory, but the more that's available to page cache the less they need to hit disk to serve reads, etc. -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
