All - I am building my first ceph cluster, and doing it "the hard way", manually without the aid of "ceph-deploy". I have successfully built the mon cluster and am now adding OSDs. My main question: How do I prepare the "Journal" prior to the prepare/activate stages of the OSD creation? More details: Basically - all of the documentation seems to "assume" the journal is "prepared". Do I simply create a single raw partition on a physical device and the "ceph-disk prepare..." and "ceph-disk activate..." steps will "take care" of everything for the journal ... presumably based on the "ceph-disk prepare ... --type" filesystem setting? Or do I need to actually format it as a filesystem prior to giving it over to the Ceph OSD ??? The architecture I'm thinking of is as follows - based on the hardware I have for OSDs (currenly 9 servers each with): RAID 0 mirror for OS hard drives (2 disks) data disk for journal placement for 5 physical disks (4TB) data disk for journal placement for 5 physical disks (4TB) 10 data disks as OSDs (one OSD per disk) (4TB each) Essentially - there are "12 data disks" in the node (all 4 TB 7200 rpm spinning disks). Splitting the Journal across two of them gives me a failure domain of "5 data disks + 1 journal disk" in a single physical server for crush map purposes ... It also vaguely helps spread the I/O workload for the journaling activity across 2 physical disks in a chassis instead of a one (since the journal disk is "pretty darn slow"). In this configuration I'd create 5 separate partitions on Journal Disk A and 5 on Journal Disk B ... but do they need to be formatted and mounted? Yes, we know as we go to more "real production" workloads, we'll want/need to change this for performance reasons - eg the Journal on SSDs ... Any pointers on where I missed this info in the documentation would be helpful too ... I've been all over the ceph.com/docs/ site and haven't found it yet... Thanks, ~~shane _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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