저널링 옵션과 쓰기 레이턴시(write latency) 테스트

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/dev/sdb7 on /snapshot type ext3 (rw,data=writeback)

[root@yum /]# time dd if=/dev/zero of=/snapshot/testfile bs=1024 count=2048000(write a 2Gfile)
2048000+0개의 레코드를 입력하였습니다
2048000+0개의 레코드를 출력하였습니다

real    0m52.466s
user    0m0.288s
sys     0m7.816s

[root@yum snapshot]# time cat testfile (when test file was 20M file)

real    0m14.482s
user    0m0.004s
sys     0m0.100s

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/dev/sdb7 on /snapshot type ext3 (rw,data=ordered)

[root@yum /]# time dd if=/dev/zero of=/snapshot/testfile bs=1024 count=2048000(write a 2Gfile)
2048000+0개의 레코드를 입력하였습니다
2048000+0개의 레코드를 출력하였습니다

real    0m58.093s
user    0m0.308s
sys     0m8.521s

[root@yum snapshot]# time cat testfile(when test file was 20M file)

real    0m14.630s
user    0m0.000s
sys     0m0.108s

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/dev/sdb7 on /snapshot type ext3 (rw,data=journal)

[root@yum /]# time dd if=/dev/zero of=/snapshot/testfile bs=1024 count=2048000(write a 2Gfile)
2048000+0개의 레코드를 입력하였습니다
2048000+0개의 레코드를 출력하였습니다

real    2m0.996s
user    0m0.272s
sys     0m8.805s

[root@yum snapshot]# time cat testfile(when test file was 20M file)

real    0m14.275s
user    0m0.000s
sys     0m0.120s
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* 참고링크: http://www.ibm.com/developerworks/kr/library/l-fs8.html