Hi All, I looking at starting to move my deployed ceph cluster to SSD. As a first step my though is to get a large enough set of SSD expantion that I can set crush map to ensure 1 copy of every (important) PG is on SSD and use primary affinity to ensure that copy is primary. I know this won't help with writes, but most of my pain is reads since workloads are generally not cache freindly and write workloads while larger ard fairly asynchronous so WAL and DB on SSD along with soem write back caching on libvirt side (most of my load is VMs) makes writes *seem* fast enough for now. I have a few question before writing a check that size. Is this completely insane? Are there any hidden surprizes I may not have considered? Will I really need to mess with crush map to get this to happen? I expect so, but if primary affinity settings along with current "rack" level leaves is good enough to be sure each of 3 replicas is in a different rack and at least one of those is on an SSD OSD I'd rather not touch crush (bonus points if anyone has a worked example). Thanks, -Jon _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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