Hi, On 04/06/15 02:26, Francois Lafont wrote: > Hi, > > Lionel Bouton wrote : > >> Sorry this wasn't clear: I tried the ioprio settings before disabling >> the deep scrubs and it didn't seem to make a difference when deep scrubs >> occured. > I have never tested these parameters (osd_disk_thread_ioprio_priority and > osd_disk_thread_ioprio_class), but did you check that the I/O scheduler of > the disks is cfq? Yes I did. > Because, if I understand well, these parameters have no > effect if the I/O scheduler is no cfq AFAIK cfq is the only elevator supporting priorities in the mainline kernel. > and, for instance, in Ubuntu 14.04 > the I/O scheduler is deadline by default (not cfq). > > By the way, even if I don't use these parameters, should I use cfq I/O > scheduler instead of deadline? Is there a best I/O scheduler for Ceph? It probably depends on your actual workload. It may depend on your hardware too: some benchmarks have shown it to perform faster on HDD but slower than deadline or noop on SSD. -- Lionel Bouton _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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