I just installed CentOS 5.4 64 bit release on a 1.9ghz CPU with 8gB of RAM. It has 2 Western Digital 1.5TB SATA2 drives in RAID1. [root at server ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/md2 1.4T 1.4G 1.3T 1% / /dev/md0 99M 19M 76M 20% /boot tmpfs 4.0G 0 4.0G 0% /dev/shm [root at server ~]# Its barebones right now. Nothing really running. I intended to move our current email server over to it eventually. The thing is slow as mud due to disk I/O though. I have no idea whats going on. Here is a bit of iostat -x output. [root at server ~]# iostat -x Linux 2.6.18-164.9.1.el5 (server.x.us) 01/05/2010 avg-cpu: %user %nice %system %iowait %steal %idle 0.13 0.10 0.03 38.23 0.00 61.51 Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util sda 0.18 0.33 0.04 0.20 27.77 4.22 132.30 3.70 15239.91 2560.21 61.91 sda1 0.00 0.00 0.00 0.00 0.34 0.00 654.72 0.01 12358.84 3704.24 0.19 sda2 0.18 0.00 0.04 0.00 27.30 0.00 742.93 0.30 8065.37 1930.35 7.09 sda3 0.00 0.33 0.01 0.20 0.14 4.22 21.29 3.40 16537.41 3008.03 61.52 sdb 0.19 0.33 0.06 0.20 28.39 4.22 126.29 2.51 9676.49 862.49 22.27 sdb1 0.00 0.00 0.00 0.00 0.34 0.00 606.29 0.00 2202.03 643.13 0.04 sdb2 0.18 0.00 0.04 0.00 27.30 0.00 724.25 0.10 2579.45 745.76 2.81 sdb3 0.01 0.33 0.02 0.20 0.75 4.22 22.61 2.41 10913.16 988.40 21.74 md2 0.00 0.00 0.04 0.48 0.89 3.87 9.04 0.00 0.00 0.00 0.00 md1 0.00 0.00 0.00 0.00 0.00 0.00 8.00 0.00 0.00 0.00 0.00 md0 0.00 0.00 0.00 0.00 0.00 0.00 7.20 0.00 0.00 0.00 0.00 Does anyone have an idea what I have wrong here? This is my first software RAID install. Built a number of Centos servers without RAID and they have all worked fine. Matt