http://www.cyberciti.biz/tips/top-linux-monitoring-tools.html
9个免费的linux系统镜像软件，监控服务器
http://www.linuxlinks.com/article/20090709183715280/SystemMonitoring.html
top,vmstat（软硬件信息）,w(用户信息),uptime(负载信息),ps,free,iostat,sar,mpstat,pmap（某进程的具体内存使用）,netstat,ss(查看本地端口与远程主机端口连接),iptraf(实时的网卡监控),tcpdump(详细的网络传输数据包分析),strace,proc file(系统自带的/proc/cpuinfo meminfo zoneinfo mounts),Nagios,cacti,kde,gnome
A few more tools:
nmap - scan your server for open ports.
lsof - list open files, network connections and much more.
ntop web based tool - ntop is the best tool to see network usage in a way similar to what top command does for processes i.e. it is network traffic monitoring software. You can see network status, protocol wise distribution of traffic for UDP, TCP, DNS, HTTP and other protocols.
Conky - Another good monitoring tool for the X Window System. It is highly configurable and is able to monitor many system variables including the status of the CPU, memory, swap space, disk storage, temperatures, processes, network interfaces, battery power, system messages, e-mail inboxes etc.
GKrellM - It can be used to monitor the status of CPUs, main memory, hard disks, network interfaces, local and remote mailboxes, and many other things.
vnstat - vnStat is a console-based network traffic monitor. It keeps a log of hourly, daily and monthly network traffic for the selected interface(s).
htop - htop is an enhanced version of top, the interactive process viewer, which can display the list of processes in a tree form.
mtr - mtr combines the functionality of the traceroute and ping programs in a single network diagnostic t
全部掌握即可快速定位服务器系统性能瓶颈