kvm磁盘io优化以及性能测试以及与物理机对比

<driver name='qemu' type='qcow2'/>
<source file='/kvm-data/kvm/wcltest2_os_disk.qcow2'/>
<backingStore/>
<target dev='hda' bus='ide'/>
<alias name='ide0-0-0'/>
<address type='drive' controller='0' bus='0' target='0' unit='0'/>

<driver name='qemu' type='qcow2' cache='none' io='native'/>
<target dev='vda' bus='virtio'/>
同时删除
<address type='drive' controller='0' bus='0' target='0' unit='0'/>

wget https://github.com/akopytov/sysbench/archive/1.0.zip -O "sysbench-1.0.zip"
unzip sysbench-1.0.zip
apt-get install automake -y
apt-get install libtool -y
./autogen.sh
./configure --without-mysql
备注（ --without-mysql 不编译测试mysql的相关环境）
make
make install

sysbench --test=fileio --num-threads=50 --file-total-size=2G --file-test-mode=rndrw prepare  准备测试
sysbench --test=fileio --num-threads=50 --file-total-size=2G --file-test-mode=rndrw run      开始测试
sysbench --test=fileio --num-threads=50 --file-total-size=2G --file-test-mode=rndrw cleanup  清除测试文件

File operations:
reads/s:                      469.90
writes/s:                     312.81
fsyncs/s:                     1000.35

Throughput:
read, MiB/s:                  7.34
written, MiB/s:               4.89

General statistics:
total time:                          10.1041s
total number of events:              18024

Latency (ms):
min:                                    0.00
avg:                                   27.86
max:                                 1047.11
95th percentile:                      153.02
sum:                               502103.21

Threads fairness:
events (avg/stddev):           360.4800/49.51
execution time (avg/stddev):   10.0421/0.03

reads/s:                      243.34
writes/s:                     162.23
fsyncs/s:                     513.40

Throughput:
read, MiB/s:                  3.80
written, MiB/s:               2.53

General statistics:
total time:                          10.1048s
total number of events:              9290

Latency (ms):
min:                                    0.00
avg:                                   54.13
max:                                  769.09
95th percentile:                      297.92
sum:                               502877.36

Threads fairness:
events (avg/stddev):           185.8000/65.60
execution time (avg/stddev):   10.0575/0.02

File operations:
reads/s:                      438.57
writes/s:                     289.51
fsyncs/s:                     911.55

Throughput:
read, MiB/s:                  6.85
written, MiB/s:               4.52

General statistics:
total time:                          10.1056s
total number of events:              16577

Latency (ms):
min:                                    0.01
avg:                                   30.30
max:                                  311.64
95th percentile:                      123.28
sum:                               502289.90

Threads fairness:
events (avg/stddev):           331.5400/28.37
execution time (avg/stddev):   10.0458/0.02