On 06/26/2015 08:23 AM, Alex Gorbachev wrote: > I would not do this, MONs are very important and any load or stability > issues on OSD nodes would interfere with the cluster uptime. I found > it acceptable to run MONs on virtual machines with local storage. But > since MONs oversee OSD nodes, I believe combining them is a recipe for > disaster, FWIW. > I fully agree. Technically it COULD work, but I would vote against it. Three simple Atom [0] machines with a local SSD will do the job just fine for most smaller Ceph cluster. Wido [0]: http://www.supermicro.nl/products/system/1U/5018/SYS-5018A-TN4.cfm > Regards, > Alex > > On Thu, Jun 25, 2015 at 12:37 PM, Shane Gibson > <Shane_Gibson@xxxxxxxxxxxx> wrote: >> >> For a small deployment this might be ok - but as mentioned, mon logging >> might be an issue. Consider the following: >> >> * disk resources for mon logging (maybe dedicate a disk to logging, to >> avoid disk IO contention for OSDs) >> * CPU resources, some Filesystem types for OSDs can eat a lot of CPU >> (that' good, they're doing hard work, your using those resources to gain >> performance!!) >> * consider memory pressure of both mons and OSDs - Filesystem cache in >> memory is a good thing, are you going to be impacting that w/ comingling >> mons? >> >> If you have fairly decent machines with more cores/HTs than OSD disks, you >> probably don't have a huge CPU issue to worry about (...probably...). >> >> ~~shane >> >> On 6/25/15, 9:23 AM, "ceph-users on behalf of Quentin Hartman" >> <ceph-users-bounces@xxxxxxxxxxxxxx on behalf of >> qhartman@xxxxxxxxxxxxxxxxxxx> wrote: >> >> The biggest downside that I've found is the log volume that mons create eats >> a lot of io. I was running mons on my OSDs previously, but in my current >> dpeloyment I've moved them to other hardware and noticed a perceptible load >> reduction on those nodes that were formerly running mons. >> >> QH >> >> On Thu, Jun 25, 2015 at 10:21 AM, Lazuardi Nasution <mrxlazuardin@xxxxxxxxx> >> wrote: >>> >>> Hi, >>> >>> I'm looking for pros and cons of combining MON and OSD functionality on >>> the same nodes. Mostly recommended configuration is to have dedicated, odd >>> number MON nodes. What I'm thinking is more like single node deployment but >>> consist more than one node, if we have 3 nodes we have 3 MONs with 3 OSDs. >>> Since MON will only consume small resources, I think MON load will not >>> degrade OSD performance significantly. If we have odd number of nodes, we >>> can still maintain the quorum of MON with this way. Any idea? >>> >>> Best regards, >>> >>> >>> _______________________________________________ >>> ceph-users mailing list >>> ceph-users@xxxxxxxxxxxxxx >>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >>> >> >> >> _______________________________________________ >> ceph-users mailing list >> ceph-users@xxxxxxxxxxxxxx >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >> > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > -- Wido den Hollander 42on B.V. Ceph trainer and consultant Phone: +31 (0)20 700 9902 Skype: contact42on _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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