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Swap files are also much easier to set up than partitions if you're using full disk encryption.
Earlier quoted context omitted.
> does anyone know why In a nutshell, overcommit. It's more or less broken by design but it's also incredibly practical so pretty much everyone does it. Couple that with the fact that it's difficult bordering on impossible to correctly determine the culprit. If you've got 16 GB RAM and the user launches 3 processes each of which attempts to use 8 GB who should you kill?
Notably windows doesn't use overcommit, and degrades much more gracefully under memory pressure. The biggest tradeoff is the amount of disk space consumed by a page file that also has to reserve space for unused pages that have been allocated but never been swapped in. On linux you can turn overcommit off, but there's too much software written around the assumption that overcommit is on
Earlier quoted context omitted.
It also doesn't sound like a particularly good idea on BTRFS, judging by the linked documentation: https://btrfs.readthedocs.io/en/latest/Swapfile.html
And since you should probably be running a modern CoW filesystem then you probably shouldn't be using swapfiles ... is the conclusion I arrived at anyway. Either install multiple times more RAM than you need and enable zswap or else set aside a swap partition as has always been done.
Oh, the irony of: echo "/swapfile none swap defaults 0 0" >> /etc/fstab If we are going full modern, why not create a Systemd unit? ( https://www.freedesktop.org/software/systemd/man/latest/syst... ) if you need more info. If you didn't know this: /etc/fstab is not used directly after the pivot. Systemd parses it, creates units for every record in it, and that's what gets executed in reality. I can't imagine why woul…
For swap, the best advice is to disable swap on your desktop, unless <8GB RAM. Really, I've never needed it and you probably won't either.
Every rule has an exception. Beware of this advice on zfs, for instance. Meanwhile zswap (of no relation with zfs) is free performance. Is it a rule that everything starting with a 'z' must be cool?
And if I have a separate otherwise unused ssd then using a swap partition simply is easier than creating a file system for it and mounting it somewhere. Block level backups also are easier.
What would be nice about swap files is if they could dynamically grow and shrink without a special setup.
Way too many variables on Linux for a one size fits all.
Stop using partitions. Use LVM!
(ZFS might be described as the love child of lvm and btrfs, 'cept ZFS got there first)
( Very briefly: you hand ZFS a stack of disks (in mirrors or raidz groups, for redundancy) and it makes a zpool. Then you carve the pool into datasets as needed. Each dataset looks like an ordinary directory and takes only the space its files actually use, so you never guess partition sizes again. And each one can have its own compression, snapshot schedule, quota, encryption, and send/receive backups, etc etc etc. )
Remember when distros used complicated partition setups, one for /root, one for /var one for /home, a swap partition etc. Was always a bad choice because one of them would be at 99% while others would linger below 10% For swap, the best advice is to disable swap on your desktop, unless <8GB RAM. Really, I've never needed it and you probably won't either.
Tangential, but does anyone know why in 2026 and on Debian 13, my machine still hangs when some process exhausts RAM? Is there really no higher-priority kernel process to prevent total freeze of the system and send a SIGKILL to the culprit process when such a scenario happens?
This has finally been fixed in the latest Ubuntu version (26), it now force closes the culprit.
And since that happened on all nodes around the same time, it took out the entire cluster. If you are not familiar, random, uncontrolled node restarts in any kind of multi node database or search product are a great way to trigger outages. So, not great.
I've had quite a few encounters with the oomkiller killing processes that were important and didn't need killing. Or as I like to phrase it "killing the one reason this server exists".
These days the way to size a server is "have enough memory to run whatever you need running + at least half a GB for whatever apt might randomly demand at any point". And guess what, memory tends to be expensive in cloud environments so people tend to get vms with as little as half a GB of ram.