Filesystems comparison using iozone

This is an update of the previous test using Iozone. These tests are divided into 2 parts:
- Performance measurement using a normal environnement which will show us the behaviour of the different filesystem using the buffer cache.
- Real I/O performance on a low memory system.

The kernel tested is a 2.6.22-rc5 on a 4way machine (2 Intel Xeon 2.80GHz HT) 2GB of RAM with a 68GB SCSI ultra320 10 000rpm disk. 3 differents filesystems were tested, XFS using default setting, Ext3 with data=writeback option and Ext4 with data=writeback,delalloc,extents options. Therefore the kernel was patched with the last ext4 patches

Test sequence:

mount -t ext3 -o data=writeback
mount -t ext4dev -o data=writeback,extents,delalloc
mount -t xfs

iozone -az -g max_file_size -n min_file_size -y min_record_size -q max_record_size -i 0 -i 1 -i 2 -f /mnt/test/iozonetest

I/O Performance

In order to get real I/O performance, I used the "mem=64M" boot option, and ran Iozone several time with a record size from 4MB to 16MB and file size starting from 256MB to 2GB. A file size of 2GB with a record size of 8MB, has been taken as a reference.