ext3 comes by default on a lot of linux distributions (even SuSE/Novell stops using reiserfs and switchs back to ext3 now ...). It's a robust filesystem but sometimes people complain about the fact that it's maybe not the fastest fs to use ... Jim Perrin wrote a good overview of possible tweaks for ext3 on the CentOS wiki : http://wiki.centos.org/HowTos/Disk_Optimization