Help, My System Just Got Really Slow

Diagnosis:

1. Run ps or top:  Is there any process run away? (CPU usage > 50%)

2. Check the load average with uptime,  check if CPU is ever idle
    with vmstat or sar -u

3. Run vmstat (or sar -g): how much paging is going on?
    ( too many page-out: contention for memory)

    Q: Suppose you find a particular process is at fault,  What to do?
    A: Nothing!
    Why? some processes are bound to slow down the system

4. Restrict a process's consumption with limit

5. Run traceroute, ping, or netstat: is network overloaded?

6. Is server-related delays?

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