On Mon, Dec 31, 2012 at 9:14 AM, Miles Fidelman <mfidelman@xxxxxxxxxxxxxxxx> wrote: > > > Which raises another question: how are you combining drives within each OSD (raid, lvm, ?). > I'm not combining them, just running an OSD per data disk. On this cluster it's 2 disks for each of the 3 nodes. I ended up that way only because I added the second disk to each node after getting started. There was an inktank blog post not too long ago about the performance of RAID'ed disks on OSDs that might provide quantitative justification for which route to go. Like Wido suggests, I also use a shared SSD for journal on each node. The journal's not really about speeding recovery from failed OSDs/disks, it's about being able to ACK writes faster and still retain integrity when Bad Things happen. If you're RAIDing with a battery-backed cache I think you can run without a journal, but I don't know the details on that. Matthew -- 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
