[SOLVED] FSTAB adding file as swap

mackowiakp · 03-18-2019, 03:08 AM

I created on nanoPI (Ubuntu Xenial) swap file on attached USB SSD HDD partition (not seperate partition but already existing) using such commands:

Code:

$ dd if=/dev/zero of=/path/to/swapfile bs=1M count=1024 # For 1GB swap file
$ mkswap /path/to/swapfile
$ swapon /path/to/swapfile

And set in /etc/sysctl.conf

Code:

vm.swappiness = 10

My current /etc/fstab file looks like this:

Code:

LABEL=DYSK /home/pi/domoticz ext4 defaults,noatime,rw 1 2
/home/pi/domoticz/log /var/log none rw,bind 0 0
LABEL=4TB /home/pi/4TB ext4 defaults,noauto,noatime,rw 0 0
tmpfs /home/pi/ramdisk tmpfs nodev,nosuid,noexec,nodiratime,size=150K,uid=pi,gid=pi 0 0
tmpfs /var/LOG tmpfs nodev,nosuid,size=10M 0 0
media:/TMP /home/pi/MEDIA nfs rw,noauto,soft 0 0

Where LABEL=DYSK is related to /dev/sda1, that is 120 GB SSD HDD (connected via USB).

My question is. What is the proper syntax of entry in /etc/fstab for swap file (not partition) to be mounted automatically during boot time?

berndbausch · 03-18-2019, 03:40 AM

https://askubuntu.com/questions/1260...p-after-reboot

By the way, according to this page it's best not to use an SSD for file swapping. I am not sure why; I guess it must have something to do with wear and tear.

syg00 · 03-18-2019, 04:48 AM

Maybe in days of yore - no longer a consideration with modern SSD.

However, the OP has been deliberately vague as to where the swap is located - let's guess it's under /home. Timing/race problems likely await.
Then again to my eye, the entire fstab schema is somewhat bizarre, but to each his own ... :shrug:

tyler2016 · 03-18-2019, 09:03 AM

Code:

/path/to/file none            swap    sw              0       0

You might want to add a _netdev to your options to make sure that the file is available. The _netdev option means to wait until the network is available before trying to use the swap file. If it is a systemd based system, you can play around with the unit files to ensure the filesystem the swap file is on is up before it attempts to activate your swap file.