test DO disk storage

root@bazz:~# mount /dev/sda /backup/
mount: you must specify the filesystem type
root@bazz:~# mkfs
mkfs          mkfs.bfs      mkfs.cramfs   mkfs.ext2     mkfs.ext3     mkfs.ext4     mkfs.ext4dev  mkfs.fat      mkfs.minix    mkfs.msdos    mkfs.ntfs     mkfs.vfat     
root@bazz:~# mkfs
mkfs          mkfs.bfs      mkfs.cramfs   mkfs.ext2     mkfs.ext3     mkfs.ext4     mkfs.ext4dev  mkfs.fat      mkfs.minix    mkfs.msdos    mkfs.ntfs     mkfs.vfat     
root@bazz:~# mkfs.ext4 /backup/
mke2fs 1.42.9 (4-Feb-2014)
/backup/ is not a block special device.
Proceed anyway? (y,n) ^C
root@bazz:~# mkfs.ext4 /dev/sda 
mke2fs 1.42.9 (4-Feb-2014)
/dev/sda is entire device, not just one partition!
Proceed anyway? (y,n) y
Discarding device blocks: done                            
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
6553600 inodes, 26214400 blocks
1310720 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
800 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks: 
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
        4096000, 7962624, 11239424, 20480000, 23887872

Allocating group tables: done                            
Writing inode tables: done                            
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done   


root@bazz:~# mount /dev/sda /backup/
root@bazz:~# cat /proc/mounts | grep backup
/dev/sda /backup ext4 rw,relatime,data=ordered 0 0
root@bazz:~# fio --version
fio-2.1.3
[readtest]
blocksize=4k
filename=/dev/sda
rw=randread
direct=1
buffered=0
ioengine=libaio
iodepth=32

readtest: (g=0): rw=randread, bs=4K-4K/4K-4K/4K-4K, ioengine=libaio, iodepth=32
fio-2.1.3
Starting 1 process
^Cbs: 1 (f=1): [r] [10.6% done] [12091KB/0KB/0KB /s] [3022/0/0 iops] [eta 01h:44m:04s]
fio: terminating on signal 2

readtest: (groupid=0, jobs=1): err= 0: pid=1938: Wed Jul 13 16:53:29 2016
  read : io=10831MB, bw=15022KB/s, iops=3755, runt=738324msec
    slat (usec): min=2, max=28634, avg=26.59, stdev=140.05
    clat (usec): min=31, max=641654, avg=8484.77, stdev=5636.90
     lat (usec): min=124, max=641659, avg=8512.38, stdev=5637.37
    clat percentiles (usec):
     |  1.00th=[ 1240],  5.00th=[ 2640], 10.00th=[ 3376], 20.00th=[ 4384],
     | 30.00th=[ 5280], 40.00th=[ 6240], 50.00th=[ 7200], 60.00th=[ 8256],
     | 70.00th=[ 9664], 80.00th=[11456], 90.00th=[15040], 95.00th=[19072],
     | 99.00th=[29056], 99.50th=[34048], 99.90th=[45824], 99.95th=[50944],
     | 99.99th=[64256]
    bw (KB  /s): min= 7181, max=23616, per=100.00%, avg=15036.10, stdev=2447.42
    lat (usec) : 50=0.01%, 100=0.01%, 250=0.04%, 500=0.14%, 750=0.22%
    lat (usec) : 1000=0.28%
    lat (msec) : 2=1.80%, 4=13.47%, 10=56.35%, 20=23.44%, 50=4.19%
    lat (msec) : 100=0.05%, 250=0.01%, 500=0.01%, 750=0.01%
  cpu          : usr=5.15%, sys=14.07%, ctx=1508861, majf=0, minf=40
  IO depths    : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=100.0%, >=64=0.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.1%, 64=0.0%, >=64=0.0%
     issued    : total=r=2772756/w=0/d=0, short=r=0/w=0/d=0

Run status group 0 (all jobs):
   READ: io=10831MB, aggrb=15021KB/s, minb=15021KB/s, maxb=15021KB/s, mint=738324msec, maxt=738324msec

Disk stats (read/write):
  sda: ios=2772591/157, merge=0/10, ticks=23101308/4188, in_queue=23105120, util=100.00%