Hi,
same environment, after a test script, the io latency(get from sudo ceph --admin-daemon /run/ceph/guests/ceph-client.*.asok per dump)
increase from about 4ms to 7.3ms
qemu version: debian 2.1.2
kernel:3.10.45-openstack-amd64
system: debian 7.8
ceph: 0.94.5
VM CPU number: 4 (cpu MHz : 2599.998)
VM memory size: 16GB
9 OSD storage servers, with 4 SSD OSD on each, total 36 OSDs.
Test scripts in VM:
# cat reproduce.sh
#!/bin/bash
times=20
for((i=1;i<=$times;i++))
do
tmpdate=`date "+%F-%T"`
echo "=======================$tmpdate($i/$times)======================="
tmp=$((i%2))
if [[ $tmp -eq 0 ]];then
echo "############### fio /root/vdb.cfg ###############"
fio /root/vdb.cfg
else
echo "############### fio /root/vdc.cfg ###############"
fio /root/vdc.cfg
fi
done
tmpdate=`date "+%F-%T"`
echo "############### [$tmpdate] fio /root/vde.cfg ###############"
fio /root/vde.cfg
# cat vdb.cfg
[global]
rw=randwrite
direct=1
numjobs=64
ioengine=sync
bsrange=4k-4k
runtime=180
group_reporting
[disk01]
filename=/dev/vdb
# cat vdc.cfg
[global]
rw=randwrite
direct=1
numjobs=64
ioengine=sync
bsrange=4k-4k
runtime=180
group_reporting
[disk01]
filename=/dev/vdc
# cat vdd.cfg
[global]
rw=randwrite
direct=1
numjobs=64
ioengine=sync
bsrange=4k-4k
runtime=180
group_reporting
[disk01]
filename=/dev/vdd
# cat vde.cfg
[global]
rw=randwrite
direct=1
numjobs=64
ioengine=sync
bsrange=4k-4k
runtime=180
group_reporting
[disk01]
filename=/dev/vde
After run the scripts reproduce.sh, the disks in the VM's IOPS cutdown from 12k to 5k, the latency increase from 4ms to 7.3ms.
run steps:
1. create a VM
2. create four volumes and attatch to the VM
3. sh reproduce.sh
4. in the runtime of reproduce.sh, run "fio vdd.cfg" or "fio vde.cfg" to checkt the performance
After reproduce.sh finished, performance down.
Anyone has the same problem or has some ideas about this?
Thanks!
--------------
hzwulibin
2015-11-02
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