> One downside of the above arrangement: I read that support for mapping > newer-format RBDs is only present in fairly recent kernels. I'm running > Ubuntu 12.04 on the cluster at present with its stock 3.2 kernel. There > is a PPA for the 3.11 kernel used in Ubuntu 13.10, but if you're looking > at a new deployment it might be better to wait until 14.04: then you'll > get kernel 3.13. > > Anyone else have any ideas on the above? I don't think there are any hairy udev issues or similar that will make using a newer kernel on precise problematic. The only thing I can think of that is a caveat of this kind of setup if if you lose a hypervisor the cache will go with it and you likely wont be able to migrate the guest to another host. The alternative is to use flashcache on top of the OSD partition but then you introduce network hops and is closer to what the tiering feature will offer, except the flashcache OSD method is more particular about disk:ssd ratio, whereas in a tier the flash could be on s completely separate hosts (possibly dedicated flash machines). -- Kyle _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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