[tunning] performance tunning

gistfile1.txt

===dstat
apt-get install dstat
```
dstat -h
Usage: dstat [-afv] [options..] [delay [count]]
Versatile tool for generating system resource statistics

Dstat options:
  -c, --cpu              enable cpu stats
     -C 0,3,total           include cpu0, cpu3 and total
  -d, --disk             enable disk stats
     -D total,hda           include hda and total
  -g, --page             enable page stats
  -i, --int              enable interrupt stats
     -I 5,eth2              include int5 and interrupt used by eth2
  -l, --load             enable load stats
  -m, --mem              enable memory stats
  -n, --net              enable network stats
     -N eth1,total          include eth1 and total
  -p, --proc             enable process stats
  -r, --io               enable io stats (I/O requests completed)
  -s, --swap             enable swap stats
     -S swap1,total         include swap1 and total
  -t, --time             enable time/date output
  -T, --epoch            enable time counter (seconds since epoch)
  -y, --sys              enable system stats

  --aio                  enable aio stats
  --fs, --filesystem     enable fs stats
  --ipc                  enable ipc stats
  --lock                 enable lock stats
  --raw                  enable raw stats
  --socket               enable socket stats
  --tcp                  enable tcp stats
  --udp                  enable udp stats
  --unix                 enable unix stats
  --vm                   enable vm stats

  --plugin-name          enable plugins by plugin name (see manual)
  --list                 list all available plugins

  -a, --all              equals -cdngy (default)
  -f, --full             automatically expand -C, -D, -I, -N and -S lists
  -v, --vmstat           equals -pmgdsc -D total

  --float                force float values on screen
  --integer              force integer values on screen
  
  ```
  
===iostat
```
>> iostat -x 2 5
Linux 3.16.0-0.bpo.4-amd64 _x86_64_ (2 CPU)

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           9.22    0.00    3.35    9.28    0.00   78.14

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await r_await w_await  svctm  %util
sda               0.01   162.50    0.02  304.47     0.70  2708.98    17.80     0.84    2.77    6.70    2.77   0.72  21.87

```

==lsof -p <pid>
```  
>> lsof -p 15265
lsof: WARNING: can't stat() ext4 file system /var/lib/docker/aufs
      Output information may be incomplete.
COMMAND   PID    USER   FD   TYPE  DEVICE SIZE/OFF    NODE NAME
etcd    15265 csiuser  cwd    DIR     8,1     4096 1050225 xxxx
etcd    15265 csiuser  rtd    DIR     8,1     4096       2 /
etcd    15265 csiuser  txt    REG     8,1  8687648 1182520 yyyy
```


reference:
http://serverfault.com/questions/212661/determining-which-process-is-causing-heavy-disk-i-o