dd를 이용한 Disk IO 성능 측정

아래와 같은 스크립트로 성능 측정
자세한 설명은 추후 업데이트 예정


 #!/bin/sh

i=0

# test iteration
LOOP=10

# 1G = 51200k * 20
# 1G = 1024k * 1024
BLOCK_SIZE=51200k
COUNT=20

while [ $i -lt $LOOP ]
do
 #### initialization ##################################################################
 i=`expr $i + 1`
 echo "== $i iteration =="
 # flush file system buffer
 sync

 #### write test     ##################################################################
 # To free pagecache, dentries and inodes:
 echo 3 > /proc/sys/vm/drop_caches
 # cond=fsync: physically write output file data & metadata before finishing
 dd if=/dev/zero of=1G_file_$i  bs=$BLOCK_SIZE count=$COUNT conv=fsync 2>&1 | grep "MB"

 #### read test      ##################################################################
 # To free pagecache, dentries and inodes:
 echo 3 > /proc/sys/vm/drop_caches
 dd if=1G_file_$i  of=/dev/zero  bs=$BLOCK_SIZE 2>&1 | grep "MB"

 #### delete test file ################################################################
 rm 1G_file_$i
done