well, nice one :) *step chooseleaf firstn 0 type host* - it is the part of default crush map (3 hosts, 2 OSDs per host)
It means: write 3 replicas (in my case) to 3 hosts...and randomly select OSD from each host ? I already read all the docs...and still not sure how to proceed... On 16 October 2013 23:27, Mike Dawson <mike.daw...@cloudapt.com> wrote: > Andrija, > > You can use a single pool and the proper CRUSH rule > > > step chooseleaf firstn 0 type host > > > to accomplish your goal. > > http://ceph.com/docs/master/**rados/operations/crush-map/<http://ceph.com/docs/master/rados/operations/crush-map/> > > > Cheers, > Mike Dawson > > > > On 10/16/2013 5:16 PM, Andrija Panic wrote: > >> Hi, >> >> I have 2 x 2TB disks, in 3 servers, so total of 6 disks... I have >> deployed total of 6 OSDs. >> ie: >> host1 = osd.0 and osd.1 >> host2 = osd.2 and osd.3 >> host4 = osd.4 and osd.5 >> >> Now, since I will have total of 3 replica (original + 2 replicas), I >> want my replica placement to be such, that I don't end up having 2 >> replicas on 1 host (replica on osd0, osd1 (both on host1) and replica on >> osd2. I want all 3 replicas spread on different hosts... >> >> I know this is to be done via crush maps, but I'm not sure if it would >> be better to have 2 pools, 1 pool on osd0,2,4 and and another pool on >> osd1,3,5. >> >> If possible, I would want only 1 pool, spread across all 6 OSDs, but >> with data placement such, that I don't end up having 2 replicas on 1 >> host...not sure if this is possible at all... >> >> Is that possible, or maybe I should go for RAID0 in each server (2 x 2Tb >> = 4TB for osd0) or maybe JBOD (1 volume, so 1 OSD per host) ? >> >> Any suggesting about best practice ? >> >> Regards, >> >> -- >> >> Andrija Panić >> >> >> ______________________________**_________________ >> ceph-users mailing list >> ceph-users@lists.ceph.com >> http://lists.ceph.com/**listinfo.cgi/ceph-users-ceph.**com<http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com> >> >> -- Andrija Panić -------------------------------------- http://admintweets.com --------------------------------------
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