Hi,
we try to run fio against raw RBD devices on a ceph cluster. Here are
the parameter we use to run fio:
[test]
filename=/dev/rbd0
time_based
runtime=3h
rw=randrw
rwmixread=80
rwmixwrite=20
blocksize_range=4k-1024k
ioengine=libaio
iodepth=64
direct=1
verify=crc32c-intel
verify_fatal=1
verify_async=16
lockfile=exclusive
We see some problems:
1) fio reports higher READ speeds than the used 1Gbit network interface
could provide (the interface isn't even working to capacity in this
situation). That happens if we use --rwmixread/rwmixwrite:
READ: io=91560MB, aggrb=156206KB/s, minb=159955KB/s,
maxb=159955KB/s, mint=600216msec, maxt=600216msec
WRITE: io=22944MB, aggrb=39143KB/s, minb=40083KB/s, maxb=40083KB/s,
mint=600216msec, maxt=600216msec
2) fio 2.0.6 and also the current git tends to fail with this error:
fio 2.0.6
Starting 1 process
fio: iolog.c:242: log_io_piece: Assertion `ipo->len == __ipo->len'
failed.:08m:31s]
It seems that we can prevent it when we use the --size parameter, but we
would like to prevent the usage of the parameter, if possible
3) fio always reports minb == maxb and aggrb < minb as you can see
above. From my understanding this would be false info.
4) If we define rw=randrw, rwmixread=80, rwmixwrite=20 and the verify
options, what does the READ process if there isn't enough data written
out yet? Which data does READ read and verify?
Thanks and Regards,
Danny
--
Danny Kukawka
SUSE LINUX Products GmbH
Maxfeldstrasse 5, D-90409 Nuremberg, Germany
GF: Jeff Hawn,Jennifer Guild,Felix Imendörffer,HRB16746 (AG Nürnberg)
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