Latest update @ github
https://github.com/sjcode236/linux/blob/master/memoryCmds.py
free -m
vmstat 1
1a) Find CPU , MEM usage by a process
ps -p 8564 -o %cpu,%mem,cmd
Find out who is monopolizing or eating the CPUs
ps -eo pcpu,pmem,pid,user,args | sort -k 1 -r | head -10
or
ps -eo pcpu,pmem,pid,user,args | sort -r -k 1 | less
Find out who is monopolizing or eating the Memory
ps -eo pmem,pcpu,pid,user,args | sort -k 1 -r | head -10
or
ps -eo pmem,pcpu,pid,user,args | sort -r -k 1 | less
ps aux |sort -r -k 3|more ----> sort on cpu usage colum 3
ps aux |sort -r -k 4|more ----> sort on mem usage colum 4
ps aux | awk '{print $6/1024 " " $11}' | sort -n
5 common commands
1)free -m
free -t
2)top
3)cat /proc/meminfo
4)vmstat 1
vmstat 1 3
procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu-----
r b swpd free buff cache si so bi bo in cs us sy id wa st
0 1 4903264 255048 36276 892204 58 45 78 61 60 33 3 1 96 0 0
0 0 4903264 255040 36280 892204 0 0 0 1 248 402 1 1 99 0 0
0 0 4903264 255040 36280 892204 0 0 0 0 309 442 1 1 99 0 0
5)dmidecode -t 17 |more
# dmidecode 2.12
SMBIOS 2.4 present.
Handle 0x00E3, DMI type 17, 27 bytes
Memory Device
Array Handle: 0x00E2
Error Information Handle: No Error
Total Width: 32 bits
Data Width: 32 bits
Size: 8192 MB
Form Factor: DIMM
Set: None
Locator: RAM slot #0
Bank Locator: RAM slot #0
Type: DRAM
Type Detail: EDO
Speed: Unknown
Manufacturer: Not Specified
Serial Number: Not Specified
Asset Tag: Not Specified
drop_caches (Freeing page cache)
Writing to this will cause the kernel to drop clean caches, dentries and
inodes from memory, causing that memory to become free.
To free pagecache:
echo 1 > /proc/sys/vm/drop_caches
To free dentries and inodes:
echo 2 > /proc/sys/vm/drop_caches
To free pagecache, dentries and inodes:
echo 3 > /proc/sys/vm/drop_caches
egs:-
free -m && sync && echo 3 > /proc/sys/vm/drop_caches && free -m
echo 3 | sudo tee /proc/sys/vm/drop_caches
# free -m
total used free shared buff/cache available
Mem: 15791 10619 4383 88 788 4746
Swap: 4095 2917 1178
https://github.com/sjcode236/linux/blob/master/memoryCmds.py
free -m
vmstat 1
1a) Find CPU , MEM usage by a process
ps -p 8564 -o %cpu,%mem,cmd
Find out who is monopolizing or eating the CPUs
ps -eo pcpu,pmem,pid,user,args | sort -k 1 -r | head -10
or
ps -eo pcpu,pmem,pid,user,args | sort -r -k 1 | less
Find out who is monopolizing or eating the Memory
ps -eo pmem,pcpu,pid,user,args | sort -k 1 -r | head -10
or
ps -eo pmem,pcpu,pid,user,args | sort -r -k 1 | less
ps aux |sort -r -k 3|more ----> sort on cpu usage colum 3
ps aux |sort -r -k 4|more ----> sort on mem usage colum 4
ps aux | awk '{print $6/1024 " " $11}' | sort -n
5 common commands
1)free -m
free -t
2)top
3)cat /proc/meminfo
4)vmstat 1
vmstat 1 3
procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu-----
r b swpd free buff cache si so bi bo in cs us sy id wa st
0 1 4903264 255048 36276 892204 58 45 78 61 60 33 3 1 96 0 0
0 0 4903264 255040 36280 892204 0 0 0 1 248 402 1 1 99 0 0
0 0 4903264 255040 36280 892204 0 0 0 0 309 442 1 1 99 0 0
5)dmidecode -t 17 |more
# dmidecode 2.12
SMBIOS 2.4 present.
Handle 0x00E3, DMI type 17, 27 bytes
Memory Device
Array Handle: 0x00E2
Error Information Handle: No Error
Total Width: 32 bits
Data Width: 32 bits
Size: 8192 MB
Form Factor: DIMM
Set: None
Locator: RAM slot #0
Bank Locator: RAM slot #0
Type: DRAM
Type Detail: EDO
Speed: Unknown
Manufacturer: Not Specified
Serial Number: Not Specified
Asset Tag: Not Specified
Part Number: Not Specified
To find
swap information
cat /proc/swaps >>
will show info on each swap partition.
swapon -s
>> shows swap partitions
and info
swapon -a
>> makes all swap
partitions available as indicated in /etc/fstab.
cat /proc/sys/vm/pagecache
To see the
process use the swap memory most
Run top then press 'O' (capital letter o) followed by 'p'
then 'enter'. Now processes should be sorted by their swap usage.
To see the swap usage details
free -m
vmstat 1
vmstat 1 5
>>You need to check the swap column where si means “swap in”, and so means “swap out.” If the numbers are high, it means a lot of swapping activity which is an indicator of low memory issues. If you see swap usage by free but little active swapping, tweaking swappiness might be due.
What is your swappiness set to? cat /proc/sys/vm/swappiness
sysctl -a |grep swappiness
--Lowering swappiness to “10” is often advised
sysctl vm.swappiness=10
sysctl -w vm.swappiness=10
echo 10 > /proc/sys/vm/swappiness
--you can permanently change the system configuration by editing
“/etc/sysctl.conf”
#Set swappiness value
vm.swappiness=10
/sbin/sysctl -p
sysctl -a or sysctl -A
--You can run swapoff -a as root to swap all memory back in. Don't forget to run swapon -a afterwards to make swap available again. Note that swapoff will fail if there is not enough physical memory available to swap everything back in.
Writing to this will cause the kernel to drop clean caches, dentries and
inodes from memory, causing that memory to become free.
To free pagecache:
echo 1 > /proc/sys/vm/drop_caches
To free dentries and inodes:
echo 2 > /proc/sys/vm/drop_caches
To free pagecache, dentries and inodes:
echo 3 > /proc/sys/vm/drop_caches
egs:-
free -m && sync && echo 3 > /proc/sys/vm/drop_caches && free -m
echo 3 | sudo tee /proc/sys/vm/drop_caches
# free -m
total used free shared buff/cache available
Mem: 15791 10619 4383 88 788 4746
Swap: 4095 2917 1178
Topas usage
top -c / top c ->
list the process with commands
iostat -x 10 100
lsof
lsof -p 25385 รจ show all the files open by that process
lsof |grep grid
