On 17 December 2015 at 21:36, Francois Lafont <flafdivers@xxxxxxx> wrote:
Hi,
I have ceph cluster currently unused and I have (to my mind) very low performances.
I'm not an expert in benchs, here an example of quick bench:
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# fio --randrepeat=1 --ioengine=libaio --direct=1 --gtod_reduce=1 --name=readwrite --filename=rw.data --bs=4k --iodepth=64 --size=300MB --readwrite=randrw --rwmixread=50
readwrite: (g=0): rw=randrw, bs=4K-4K/4K-4K/4K-4K, ioengine=libaio, iodepth=64
fio-2.1.3
...
I am seeing the same sort of issue.
If i run your 'fio' command sequence on my cephfs, i see ~120 iops.
If i run it on one of the underlying osd (e.g. in /var... on the mount point of the xfs), i get ~20k iops.
On the single SSD mount point it completes in ~1s.
On the cephfs, it takes ~17min.
I'm on Ubuntu 15.10 4.3.0-040300-generic kernel.
my 'ceph -w' while this fio is running shows ~550kB/s read/write.
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