ext3/ext4-Performance-RHEL 6

EMC Backend AX4-5F. RAID-10 12 600G 1k Drives in 4G Qlogic Fibre.

So what does dd does on the  ext3 filesystems and ext4 ones. with 8MB block size

dd if=/dev/zero of=aman2 bs=8192 count=1000000
1000000+0 records in
1000000+0 records out
8192000000 bytes (8.2 GB) copied, 8.50084 s, 964 MB/s

4MB block

dd if=/dev/zero of=aman2 bs=4192 count=1000000
1000000+0 records in
1000000+0 records out
4192000000 bytes (4.2 GB) copied, 6.19781 s, 676 MB/s



Now with ext3

 dd if=/dev/zero of=aman3 bs=8192 count=1000000
1000000+0 records in
1000000+0 records out
8192000000 bytes (8.2 GB) copied, 13.7891 s, 594 MB/s

iostat is still active after these 13 secs flushing data to the disk

10/08/2011 02:23:49 PM
avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.00    0.00    2.56   10.57    0.00   86.88

Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
sda               0.00         0.00         0.00          0          0
sdb            4790.00         0.00    101200.00          0     101200
sdd            5272.00         0.00    103056.00          0     103056
sde               0.00         0.00         0.00          0          0
sdc               0.00         0.00         0.00          0          0
emcpowera     10063.00         0.00    204256.00          0     204256
dm-0          43984.00         0.00    351872.00          0     351872

Seems like ext4 is beating the hell out of ext3.Althoigh dd is not a pure performance testing but it gives  a little pinch as to what to expect.