Hi All, I've been looking, but haven't been able to find any detailed documentation about the journal usage on OSDs. Does anyone have any detailed docs they could share? My initial questions are: Is the journal always write-only? (except under recovery) I'm using BTRFS, in the default layout, which I'm thinking is very inefficient as it basically forces the discs to seek all the time. (journal partition at start of disc) Is there a documented process to relocate the journal, without re-creating the OSD? What have other people done to optimize the journal without purchasing SSD's? On another point, I'm running on HP Microservers (slow CPU - two cores) with 5 discs - 1x OS, 4x OSD... I've currently got separate OSDs, however have high load due to having more OSD's than cores in the box. I'm thinking of JBOD'ing the OSD discs into pairs using LVM (different sized disks) so I have only two OSD's, does anyone have any opinions on the merits of this? Also has anyone seen any CPU usage comparisons of XFS vs EXT4 vs BTRFS? Obviously I know I'm running an enterprise system on a shoe string, however I'm keen to use this as a test bed to get comfortable with ceph before recommending it in a real production environment, and I think optimizing and understanding it here could have great benefits when I scale out. Lots of questsions, and as ever any insight would be appreciated on any of the points! Regards Alex -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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