171. Please list the type of commonly used raid and the difference?

Please list the type of raid and the difference between frequently used?
Please outline file storage solutions you know linux operating system
You know linux kernel tuning it? Please describe the principles and parameters of superior cut.
When the linux operating system does not have / etc / sysconfig / iptables file, how to restore.
Under what conditions can use "service service name start | stop" to start the service?
Please include commonly used system tools, such as network testing, performance testing IO.
Please state your understanding of the NFS, SAN, NAS, GFS's.
Please briefly explain the principles or illustrations nagios to monitor remote servers.
Please explain the difference between LVS and three ways to achieve, and to introduce at least three algorithms.
Please include at least two dns test tools and analytically explained.