[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

ext3 peformance problem



ext3-usershello all,

	I am testing ext3 file system recently but find some problem
	I use GreatTurbo Enterprise Server 10 (Zuma) and 2.6.20 kernel
	I conducted my test 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 under different subdirs and give the performance result. 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? In /mnt/test/0 the performance is 72/80, while in /mnt/test/1 the performance is 49/53
2.	I see that the extents of all files are nearly the same, but their performances are different. What are the other factors that influence the performance except for the extents(fragmentation) of the file? 
3.	Is it true that the more files there already exists in a dir, the lower performance we will get if we test under the dir?
as in my test, the performance of /mnt/test/5/tmpfile is 66/75, while the performances of /mnt/test/5/tmpfile2 and tmpfile3 are 57/64 54/59

Thanks very much

																								


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]