To view overall performance.
[root@myserver]# top |
Note:
- By default is will sort processes based on CPU usage. Press "M" to sort based on memory usage.
To view I/O of storage devices.
[root@myserver]# iostat [root@myserver]# iostat -d #Display only disk I/O statistics [root@myserver]# iostat -n #Display on network storage devices [root@myserver]# iostat -m #Display I/O in MB/s [root@myserver]# iostat 1 3 #Display I/O every second for 3 times |
To check CPU usage at interval of 5 seconds for 3 times.
[root@myserver]# sar -u 5 3 Linux (mysever) 09/29/2013 08:31:15 PM CPU %user %nice %system %iowait %idle 08:31:20 PM all 16.92 0.00 1.48 0.15 81.45 08:31:25 PM all 14.65 0.00 0.80 0.10 84.45 08:31:30 PM all 15.85 0.00 2.02 0.07 82.05 Average: all 15.81 0.00 1.43 0.11 82.65 |
To check memory and swap utilization in megabytes.
[root@myserver]# free -m total used free shared buffers cached Mem: 3735 3567 168 0 270 2221 -/+ buffers/cache: 1075 2659 Swap: 8191 23 8168 |
To find out top 10 processes consumed the most memory.
The below command will take the output of "ps -aux", sort the memory column which is column 4 from highest value to lowest and output the first 10 results.
[root@myserver]# ps -aux |sort -nrk 4| head -10 |
To find out top 10 processes consumed the most CPU.
The below command will take the output of "ps -aux", sort the CPU column which is column 3 from highest value to lowest and output the first 10 results.
[root@myserver]# ps -aux |sort -nrk 3| head -10 |
To check how many network interface configured.
[root@myserver]# ifconfig -a eth0 Link encap:Ethernet HWaddr 11:0B:2D:EF:07:30 BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 b) TX bytes:0 (0.0 b) Interrupt:16 eth1 Link encap:Ethernet HWaddr 12:0B:44:FF:47:DF inet addr:192.0.0.1 Bcast:192.0.0.255 Mask:255.255.255.192 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:1216011503 errors:0 dropped:0 overruns:0 frame:0 TX packets:4253525258 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 b) TX bytes:0 (0.0 b) Interrupt:24 |
To check speed of eth1.
Settings for eth1: Supported ports: [ MII ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Half 1000baseT/Full Supports auto-negotiation: Yes Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Half 1000baseT/Full Advertised auto-negotiation: Yes Speed: 1000Mb/s Duplex: Full Port: Twisted Pair PHYAD: 1 Transceiver: internal Auto-negotiation: on Supports Wake-on: g Wake-on: d Current message level: 0x000000ff (255) Link detected: yes |
To check if all hard mount filesystems are mounted properly issue command "df -h" and cross check with the file /etc/fstab.
[root@myserver]# cat /etc/fstab [root@myserver]# df -h |
To check who is currently logged in.
[root@myserver]# w |
To check login history.
[root@myserver]# last |
To check current date & time on the server.
[root@myserver]# date |
To check current and previous runlevel.
The below output indicate the current runlevel is 3 and previous was 1 [Single user].
[root@myserver]# who -r run-level 3 Sep 26 06:20 last=S |
To check current and previous runlevel.
The below output indicate the current runlevel is 3 and N indicates the runlevel was not change since boot.
[root@myserver]# runlevel N 3 |
To reboot.
[root@myserver]# reboot or [root@myserver]# shutdown -r now or [root@myserver]# init 6 |
To shutdown the Operating System.
By default shutdown command will bring the Operating System to runlevel 1.
[root@myserver]# shutdown |
To shutdown the Operating System and poweroff.
[root@myserver]# shutdown -h now |
To cancel shutdown.
[root@myserver]# shutdown -c |
To list services configured.
[root@myserver]# chkconfig --list |
To start a service.
[root@myserver]# service nfs start |
To view hardware info.
[root@myserver]# dmidecode |