Hi All, Yes I'm asking the impossible question, what is the "best" hardware confing.
I'm looking at (possibly) using ceph as backing store for images and volumes on OpenStack as well as exposing at least the object store for direct use. The openstack cluster exists and is currently in the early stages of use by researchers here, approx 1500 vCPU (counts hyperthreads actually 768 physical cores) and 3T or RAM across 64 physical nodes. On the object store side it would be a new resource for usand hard to say what people would do with it except that it would be many different things and the use profile would be constantly changing (which is true of all our existing storage). In this sense, even though it's a "private cloud" the somewhat unpredictable useage profile gives it some charateristics of a small public cloud. Size wise I'm hoping to start out with 3 monitors and 5(+) OSD nodes to end up with a 20-30T 3x replicated storage (call me paranoid). So the monitor specs seem relatively easy to come up with. For the OSDs it looks like http://ceph.com/docs/master/install/hardware-recommendations suggests 1 drive, 1 core and 2G RAM per OSD (with multiple OSDs per storage node). On list discussions seem to frequently include an SSD for journaling (which is similar to what we do for our current ZFS back NFS storage). I'm hoping to wrap the hardware in a grant and willing to experiment a bit with different software configurations to tune it up when/if I get the hardware in. So my imediate concern is a hardware spec that will ahve a reasonable processor:memory:disk ratio and opinions (or better data) on the utility of SSD. First is the documented core to disk ratio still current best practice? Given a platform with more drive slots could 8 cores handle more disk? would that need/like more memory? Have SSD been shown to speed performance with this architecture? If so given the 8 drive slot example with seven OSDs presented in the docs what is the liklihood that using a high performance SSD for the OS image and also cutting journal/log partitions out of it for the remaining 7 2-3T near line SAS drives? Thanks, -Jon -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
