I have these two servers with the following specs:
OS: RHEL 6.3 Hardware: Dell PowerEdge R610, 12 cores, 64GB RAM Drives: 6 x Samsung 840 Pro SSD RAID controller: Intel RS25AB080, 1GB Cache RAID Level: 5
When we test disk performance using the dd command on server "A," we get an average of 333MB/sec.
When we test disk performance using the dd command on server "B," we get an average of 40MB/sec.
I am using the following command
dd if=/dev/zero of=testfile bs=3G count=1 oflag=dsync
I am unable to figure out why we get such terrible performance on server B.
The server is a standby cluster node for a MySQL database cluster. The active MySQL services are currently running on the other server, so this node is essentially idle. The only significant processes running on it are corosync, pacemaker, and drbd