How to review Swap space usage on a Linux server
Linux system administration is outside the scope of Atlassian support. This page is provided for your information only.
Purpose
As a system administrator, you may see the swap space fill up on the Bamboo server. The following will show some options for determining how much of the swap space each application is using.
Solution
TOP
Unix operating systems have the top command which will show memory usage. This is useful as a general overview, but SWAP is approximated as Virtual memory - Resident (physical) memory, so it less accurate than the other tools on this page.
However, once top is opened, you can sort by SWAP usage as follows:
- Type
fto open the "Add column" menu - Use the up/down arrow keys to navigate to
SWAP - Type
dor<Space>to selectSWAPfor display - Tap the right arrow to select the
SWAPcolumn to reorder - Type
sto selectSWAPas your sort column - Type
qto return to the main screen
You can save the current top configuration by typing Shift + W.
Example output:
PID USER PR NI VIRT RES SWAP SHR S %CPU %MEM TIME+ COMMAND
1 root 20 0 33492 1628 1224 1476 S 0.0 0.1 0:00.75 init
316 root 20 0 51508 1032 736 988 S 0.0 0.1 0:00.02 systemd-udevd
312 root 20 0 19472 468 252 468 S 0.0 0.0 0:00.06 upstart-udev-br
493 root 20 0 23472 208 212 208 S 0.0 0.0 0:00.00 rpc.idmapd
496 root 20 0 43444 1620 200 1460 S 0.0 0.1 0:00.00 systemd-logind
443 message+ 20 0 39212 1064 196 872 S 0.0 0.1 0:00.06 dbus-daemon
648 root 20 0 15536 756 156 384 S 0.0 0.0 0:00.02 upstart-file-br
...FREE
Another useful Linux command is free, which, when run with the -m flag, will return memory usage for your machine, including SWAP.
For example:
total used free shared buffers cached
Mem: 32109 30982 1126 0 301 2916
-/+ buffers/cache: 27764 4345
Swap: 8191 6107 2084
PROC STATUS
Finally, this command will list all applications with how much swap space each is using in kilobytes by looping through the status snapshots in the /proc/ directory:
for file in /proc/*/status ; do awk '/VmSwap|Name/{printf $2 " " $3}END{ print ""}' $file; done | sort -k 2 -n -r | less(Source)
Example:
root@bamboo:/home/vagrant# for file in /proc/*/status ; do awk '/VmSwap|Name/{printf $2 " " $3}END{ print ""}' $file; done | sort -k 2 -n -r | head
init 1008 kB
systemd-udevd 736 kB
upstart-udev-br 220 kB
dbus-daemon 192 kB
writeback
watchdog/0
vmstat
VBoxService 0 kB
upstart-socket- 0 kB
upstart-file-br 0 kB