performance
uptime
10:13:46 up 1 day, 22:09, 13 users, load average: 3.73, 3.71, 3.50
displays a system’s virtual memory statistics 10 times at 5 second intervals :
vmstat 5 10
si and so columns show the amount of data being transferred between the system’s swap and its memory.
List tcp ports that are being listened on, along with the name of each listener's daemon and its PID:
netstat -plnt
check disk perfs
dd if=/dev/zero of=/data/nobkp/VTL1/afac bs=64k count=16k conv=fdatasync
iostat -nk
XFS fragmentation :
xfs_db -c frag -r /dev/sda1
http://www.rackspace.com/knowledge_center/article/checking-system-load-on-linux