I have two servers, with similar disks.
The first server has 4x300GB Seagate Cheetah 15K.5 model nº ST3300655SS 3.5'' RAID 10. The second 4x300GB Seagate Savvio 15K.3 model nº ST9300653SS 2.5'' RAID 10.
I'm running the following command to test the write speed:
dd if=/dev/zero of=/tmp/output bs=8k count=10k; rm -f /tmp/output
On the first server with 3.5 disks I get about 1,3 GB/s write speed, while on the other only 640MB/s
Both servers run Cent OS. The faster one, CentOS 5.7 and the slower Cent OS 6.4
What could be the reason for so big difference, if both disks are 15k rpm?