Need command to create swap file

[Jay Culley]

Hi. Please excuse my noobness but I am not having much luck creating a swap file. Here is what I have done:
1: Asus RT-AC5300 running Asuswrt-merlin 380.64_1, jffs enabled, only 1 script for logging vsftpd
2: The USB 3.0 port has a 1 TB NTFS drive shared with Samba for music, movies, etc /dev/sdb1 mounted on /tmp/mnt/Exthdd
3: The USB 2 port has an inexpensive Lexar 32GB thumdrive
primary partition /dev/sda2 is 27GB mounted on /tmp/mnt/lex. Latest Entware installed
4: Also on the USB2 Lexar thumbdrive is a logical partition /dev/sda5 size 1 GB formatted Linux Swap, not mounted, no files.

So I guess I need to add an entry to fstab, then run mkswap and swapon? I need the commands with the correct syntax for the BusyBox os that Merlin runs. I am assuming my swap partition of 1GB is fine since the AC5300 has 500MB of RAM, is that correct?

thanks

jay

 

[hggomes]

You need to create the partition first ex: /dev/sda5.

# mkswap /dev/sda5
# swapon /dev/sda5

Then edit fstab:

/dev/sda5 none swap sw 0 0


or simply run "swapon /dev/sda5" command at boot script.

Yes, 1GB of swap should be fine.

 

[Jay Culley]

so, /etc/fstab was empty, now it has one line: /dev/sda5 none swap sw 0 0

the other 2 commands looked good

user@5300:/proc# mkswap /dev/sda5
Setting up swapspace version 1, size = 1047523328 bytes
UUID=17a5db57-07b2-4b98-bb72-cb6c34e0e769
user@5300:/proc# swapon /dev/sda5
user@5300:/proc#

booting...

 

[hggomes]

In order to check if it's working:

# free

 

[Jay Culley]

did not work. /proc/swaps has nothing and running the top command list no swap at the top. Should this go in /jffs/scripts in services-start or post-mount or in a conf file in /jffs/configs?

free
total used free shared buffers
Mem: 515308 125684 389624 0 536
-/+ buffers: 125148 390160
Swap: 0 0 0

 

[hggomes]

It didn't worked because the info you added to /etc/fstab was lost after a reboot, you need to add it there or run the swapon command via boot-script.

You will see it working if you manually run this:

# swapon /dev/sda5
# free

 

[bbunge]

Best instructions I've found for swap...
https://mydevtutorials.wordpress.com/2014/01/10/how-to-activate-swap-on-asus-rt-ac68u-router/

256 MEG is plenty or the same size as the router RAM. My RT-AC66U_B1 runs much better with swap on a thumb drive!

 

[Jay Culley]

OK, good to go! I ran swapon /dev/sda5 and it is now running

free
total used free shared buffers
Mem: 515308 159664 355644 0 3380
-/+ buffers: 156284 359024
Swap: 1022972 0 1022972

I added the swapon command to /jffs/scripts/post-config so it will fire off on the next boot

Thanks @hggomes !!

 

[hggomes]

You are very welcome Jay.