On 06/03/14 13:19, Gandalf Corvotempesta wrote: > 2014-03-06 13:07 GMT+01:00 David McBride <[email protected]>: >> This causes the IO load to be nicely balanced across the two SSDs, >> removing any hot spots, at the cost of enlarging the failure domain of >> the loss of an SSD from half a node to a full node. > > This is not a solution for me. > Why not using LVM with a VG striped across both SSD ? > I've never used LVM without raid, what happens in case of failure > of a phisical disks? The whole VG is lost ?
Yes. A stripe-set depends on all of the members of an array, whether managed through MD or LVM. Thus, in a machine with two SSDs, which are striped together, the loss of *either* SSD will cause all of the OSDs hosted by that machine to be lost. (Note: if you want to use LVM rather than GPTs on MD, you will probably need to remove the '|dm-*' clause from the Ceph udev rules that govern OSD assembly before they will work as expected.) Kind regards, David -- David McBride <[email protected]> Unix Specialist, University Computing Service -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
