1. Linux203Training Module
System Mgmt

2. This presentation will cover the following topics
vmstat
mpstat
lsof
uptime
uname
hostname

3. vmstat
vmstat by default will display the memory usage (including swap).
$ vmstat
procs memory swap io system cpu r b swpd free buff cache si so bi bo in cs us sy id wa st
vmstat output contains the following fields:
Procs – r: Total number of processes waiting to run
Procs – b: Total number of busy processes
Memory – swpd: Used virtual memory
Memory – free: Free virtual memory
Memory – buff: Memory used as buffers
Memory – cache: Memory used as cache.
Swap – si: Memory swapped from disk (for every second)
Swap – so: Memory swapped to disk (for every second)
IO – bi: Blocks in. i.e blocks received from device (for every second)
IO – bo: Blocks out. i.e blocks sent to the device (for every second)
System – in: Interrupts per second
System – cs: Context switches
CPU – us, sy, id, wa, st: CPU user time, system time, idle time, wait time

4. To execute every 2 seconds for 10 times $ vmstat 2 10
procs memory swap io system cpu----- r b swpd free buff cache si so bi bo in cs us sy id wa st ..

5. mpstat mpstat – Display basic info
By default mpstat displays CPU statistics
$ mpstat
Linux CAV14.fc14.x86_64 (cavisson-server-ns1) /01/ _x86_64_ (4 CPU)
02:14:39 PM CPU %usr %nice %sys %iowait %irq %soft %steal %guest %idle
02:14:39 PM all

6. Option -P ALL, displays all the individual CPUs (or Cores) along with its statistics
$ mpstat -P ALL
Linux el6.x86_64 (dev-db) 07/09/2011 _x86_64_ (4 CPU) 10:28:04 PM CPU %usr %nice %sys %iowait %irq %soft %steal %guest %idle
10:28:04 PM all :28:04 PM :28:04 PM :28:04 PM :28:04 PM

7. lsof List of open files # lsof
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
init 1 root cwd DIR 8, /
init 1 root txt REG 8, /sbin/init
init 1 root 0u CHR 1,3 0t /dev/null

8. List opened files under a directory # lsof +D /var/log/
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME rsyslogd 488 syslog 1w REG 8, /var/log/syslog rsyslogd 488 syslog 2w REG 8, /var/log/auth.log

9. uptime Displays the total uptime for the computer. $uptime
12:36:49 up 5 days, 21 min, 17 users, load average: 0.00, 0.01, 0.05

10. uname Print name of current system. $]uname -arv
Linux cavisson-server-ns CAV14.fc14.x86_64 #1 SMP Wed Sep 14 20:54:14 IST 2011 x86_64 x86_64 x86_64 GNU/Linux

11. hostname
view system name (hostname) or assign a new name to system using hostname command.
$]hostname
cavisson-server-ns1