Hi all,--
I am testing ext3 file system recently but find some problems
The platform is GreatTurbo Enterprise Server 10 (Zuma) and 2.6.20 kernel
The commands are as follows:
#mkfs.ext3 /dev/sdb1
#mount /dev/sdb1 /mnt/test
#cd /mnt/test
#mkdir 0 1 2 3 4 5 6 7
I test write and read performance with iozone under different subdirectories and list the performance results. I also use filefrag to see the file layout.
Command line used: /root/iozone -s 5g -r 1m -i 0 -i 1 -f /mnt/test/0/tmpfile -c -e -+n -w
5242880 1024 72706 0 80474 0
/mnt/test/0/tmpfile: 44 extents found, perfection would be 41 extents
Command line used: /root/iozone -s 5g -r 1m -i 0 -i 1 -f /mnt/test/ 1/tmpfile -c -e -+n -w
5242880 1024 49957 0 52899 0
/mnt/test/1/tmpfile: 42 extents found, perfection would be 41 extents
Command line used: /root/iozone -s 5g -r 1m -i 0 -i 1 -f /mnt/test/2/tmpfile -c -e -+n -w
5242880 1024 60292 0 64664 0
/mnt/test/2/tmpfile: 42 extents found, perfection would be 41 extents
Command line used: /root/iozone -s 5g -r 1m -i 0 -i 1 -f /mnt/test/ 3/tmpfile -c -e -+n -w
5242880 1024 70540 0 78644 0
/mnt/test/3/tmpfile: 46 extents found, perfection would be 41 extents
Command line used: /root/iozone -s 5g -r 1m -i 0 -i 1 -f /mnt/test/4/tmpfile -c -e -+n -w
5242880 1024 61334 0 67778 0
/mnt/test/4/tmpfile: 44 extents found, perfection would be 41 extents
Command line used: /root/iozone -s 5g -r 1m -i 0 -i 1 -f /mnt/test/ 5/tmpfile -c -e -+n -w
5242880 1024 66735 0 75114 0
/mnt/test/5/tmpfile: 42 extents found, perfection would be 41 extents
Command line used: /root/iozone -s 5g -r 1m -i 0 -i 1 -f /mnt/test/6/tmpfile -c -e -+n -w
5242880 1024 65062 0 72686 0
/mnt/test/6/tmpfile: 44 extents found, perfection would be 41 extents
Command line used: /root/iozone -s 5g -r 1m -i 0 -i 1 -f /mnt/test/7/tmpfile -c -e -+n -w
5242880 1024 69247 0 78563 0
/mnt/test/7/tmpfile: 45 extents found, perfection would be 41 extents
Command line used: /root/iozone -s 5g -r 1m -i 0 -i 1 -f /mnt/test/ tmpfile -c -e -+n -w
5242880 1024 77085 0 81696 0
Command line used: /root/iozone -s 5g -r 1m -i 0 -i 1 -f /mnt/test/ 5/tmpfile2 -c -e -+n -w
/mnt/test/5/tmpfile2: 48 extents found, perfection would be 41 extents
5242880 1024 57776 0 64870 0
Command line used: /root/iozone -s 5g -r 1m -i 0 -i 1 -f /mnt/test/5/tmpfile3 -c -e -+n -w
5242880 1024 54799 0 59145 0
/mnt/test/5/tmpfile3: 44 extents found, perfection would be 41 extents
My questions are:
1.Why the performances under different subdirs varies so much? for example in /mnt/test/0 the performance is 72/80, while in /mnt/test/1 the performance is 49/53
2.The extents of all files are nearly the same, but their performances are different. Are there other factors that influence the performance beside of the extents(fragmentation) of the file?
3.Is it true that more files exist in a directory, lower performance? for example the performance in /mnt/test/5/tmpfile is 66/75, while the performances in /mnt/test/5/tmpfile2 and tmpfile3 are 57/64 and 54/59
Thanks
National Research Center for Intelligent Computing Systems
Institute of Computing Technology, Chinese Academy of Sciences
