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Note that we pinged myftp but results come from host myhost. This is a reliable hint that you are addressing an alias, not the actual host.
== Check CPU, Memory and HDD ==
=== CPU ===
; CPU Info
lscpu
lshw -C CPU
hardinfo ==> sudo apt install hardinfo
nproc
sudo dmidecode -t 4
cpuid
cat /proc/cpuinfo
cat /proc/cpuinfo | grep processor | wc -l
* The number of processors shown by /proc/cpuinfo might not be the actual number of cores on the processor.
* For example a processor with 2 cores and hyperthreading would be reported as a processor with 4 cores.
* If there are 4 different core ids, this indicates that there are 4 actual cores.
# cat /proc/cpuinfo | grep 'core id'
core id : 0
core id : 2
core id : 1
core id : 3
; CPU Usage
top -o %CPU
htop
vmstat
sar 1 3 ==> yum install sysstat
iostat ==> yum install sysstat
; Top Command
<pre>
top - 01:07:37 up 2:40, 1 user, load average: 0.37, 0.37, 0.39
Tasks: 286 total, 1 running, 285 sleeping, 0 stopped, 0 zombie
%Cpu(s): 4.7 us, 1.6 sy, 0.0 ni, 93.8 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
MiB Mem : 15935.7 total, 9403.3 free, 3045.2 used, 3487.1 buff/cache
MiB Swap: 4100.0 total, 4100.0 free, 0.0 used. 11720.3 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
6865 aman 20 0 982620 85280 53716 S 6.2 0.5 2:52.77 Xorg
10082 aman 20 0 3537624 285448 118848 S 6.2 1.7 5:45.24 gnome-shell
</pre>
CPU Section
us user cpu time % CPU time spent in user space
sy system cpu time % CPU time spent in kernel space
ni user nice cpu time % CPU time spent on low priority processes
id idle cpu time % CPU time spent idle
wa io wait cpu time % CPU time spent in wait (on disk)
hi hardware irq % CPU time spent servicing/handling hardware interrupts
si software irq % CPU time spent servicing/handling software interrupts
st steal time % CPU time stolen from a virtual machine
Main Section:
%MEM directly related to RES, percentage use of total physical memory by the process.
VIRT total memory that this process has access to shared memory, mapped pages, swapped out pages, etc.
RES total physical memory used shared or private that the process has access to.
SHR total physical shared memory that the process has access to.
RES is most close to the memory used by the process in memory, excluding what’s swapped out.
This includes the SHR (shared physical memory) which mean it could have been used by some other process as well.
;Obtain the PID:
pgrep -n python
pidof chrome - return all PIDs
pidof -s chrome - return only 1 PID
ps -C chrome -o pid= - C = CMD
=== Memory ===
;Info
dmidecode -t 17
;Usage
cat /proc/meminfo ==> egrep --color 'Mem|Cache|Swap' /proc/meminfo
top -o %MEM
free -m
total used free shared buff/cache available
Mem: 15935 3046 9470 767 3418 11787
Swap: 4099 0 4099
vmstat
vmstat -s ==> More detailed
htop
;Per Process usage check
ps -o pid,user,%mem,command ax | sort -b -k3 -r
sudo pmap 917 ==> Libraries, other files, etc usage of memory
sudo pmap 917 | tail -n 1 ==> Total used by this process
=== HDD ===
du -h ==> space by dir including all subdir in dir tree
du -sh /etc/ ==> total disk space used by dir and suppress subdir
du -ah /etc/ ==> see all files, not just directories:
df -h
Filesystem Type Size Used Avail Use% Mounted on
/dev/sda4 ext4 77G 51G 22G 71% /
df -T -h ==> List Filesystem type as well
df -t ext4 ==> Only see ext4 file system
df -a ==> List all filesystems that have a size of zero blocks as well
df -i ==> Display File System Inodes
lsblk ==> Lists out all the storage blocks, which includes disk partitions and optical drives
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 1.8T 0 disk
├─sda1 8:1 0 500M 0 part /boot/efi
├─sda2 8:2 0 128M 0 part
sudo fdisk -l ==> Partition & FS Type details
parted ==> List out partitions and modify them
== Check IP and DNS info ==
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