Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Stop making swap partitions—use swap files instead

gist.github.com

Post reply on HN
Print view View original

51–60 of 256 posts

Re: Stop making swap partitions—use swap files instead

#51

Post by holowoodman »

Kim_Bruning wrote: post #48
holowoodman wrote: post #9

Stop using partitions. Use LVM!

Stop using LVM. Use ZFS! (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…

ZFS is overrated and mostly a hobbyist/enthusiast thing.

Performance of zvol is worse than for LVM logical volumes. Last I've looked, zvol for swap is just asking for trouble, up to and including deadlocks. ZFS filesystems do have weird edge cases and incompatibilities, e.g. around free space reporting, quota and the like. And support with software vendors e.g. for enterprise distributions or backup software is spotty at best.

Re: Stop making swap partitions—use swap files instead

#52

Post by jenders »

Kim_Bruning wrote: post #48
holowoodman wrote: post #9

Stop using partitions. Use LVM!

Stop using LVM. Use ZFS! (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…

Not a btrfs user but OpenZFS u til recently didn’t even support O_DIRECT and may still duplicate page cache in arc. It’s not well suited as a general purpose FS where you can’t anticipate the workload, like on a desktop.

Re: Stop making swap partitions—use swap files instead

#53

Post by jenders »

holowoodman wrote: post #51
Kim_Bruning wrote: post #48

Earlier quoted context omitted.

Stop using LVM. Use ZFS! (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…

ZFS is overrated and mostly a hobbyist/enthusiast thing. Performance of zvol is worse than for LVM logical volumes. Last I've looked, zvol for swap is just asking for trouble, up to and including deadlocks. ZFS filesystems do have weird edge cases and incompatibilities, e.g. around free space reporting, quota and the like. And support with software vendors e.g. for enterprise distributions or backup software is spott…

>> ZFS is overrated and mostly a hobbyist/enthusiast thing.

Not true at all.. but most large object storage redundancy has moved to the application layer. There are still workloads that are a great fit but I agree OpenZFS is currently not well suited as a general purpose FS.

Re: Stop making swap partitions—use swap files instead

#54

Post by avhception »

cedilla wrote: post #34
killerstorm wrote: post #19

Earlier quoted context omitted.

MacOS has no problem with hibernation because hardware and software are designed together: it uses TPM to manage swap encryption. I assume "BIOS" is also optimized to enable fast boot on sleep. Linux can work with TPM but it's never as smooth. (Unless I guess you make it custom for your specific setup.)

I have FDE with keys in the TPM. It's pretty smooth bit required a one time additional step in Fedora. It's also probably not very secure, but my threat model is simple theft.

What's the benefit of using the TPM compared to a simple passphrase at boot, in that scenario?

Re: Stop making swap partitions—use swap files instead

#55

Post by tacomagick »

williebeek wrote: post #46

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.

Id always suggest at least 2-4G of swap even if you have plenty of memory 32g+ because for that rare edge case where you'd really not want to OOM.

Re: Stop making swap partitions—use swap files instead

#57

Post by kaelwd »

0xbadcafebee wrote: post #7
charcircuit wrote: post #6

Linux distros that do use swap files do so statically. It doesn't handle dynamically growing and shrinking it like other operating systems.

Unless you use the Linux package that does manage swap files dynamically.

https://github.com/Tookmund/Swapspace

Re: Stop making swap partitions—use swap files instead

#58

Post by cassianoleal »

BoredomIsFun wrote: post #35
ducktective wrote: post #14

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?

It does not if you switch swapp off and use zram instead. I am typing right now on such a setup wityh 16 GiB ram and it occasionally, once a week or so, kills my firefox due to oom. If you are you using disk swap - not sure why would if you have a SSD, but I once heard some justification for doing that - then install early OOM.

> switch swapp off and use zram instead

Or zswap instead of zram.

https://chrisdown.name/2026/03/24/zswap-vs-zram-when-to-use-...

https://linuxblog.io/zswap-better-than-zram/

Re: Stop making swap partitions—use swap files instead

#59

Post by wongarsu »

fc417fc802 wrote: post #43
wongarsu wrote: post #40

Earlier quoted context omitted.

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

Is that still the case today? Notably (IIUC) overcommit is required for certain security measures. I believe it was chromium that I noticed mmaping somewhere north of 1 TB of memory on startup so that it can do (again IIUC) something akin to ASLR internally.

On Windows you can achieve something like manual overcommit by calling VirtualAlloc with just MEM_RESERVE. That gives you a continuous space in your process's virtual address space, without actually backing it with any physical pages. Kind of like what a malloc does on linux

But where linux would automagically back those pages once you use them, Windows requires you to actually ask for those pages to be backed by something (physical memory or page file) by calling VirtualAlloc with MEM_COMMIT on the range you actually want to use

Re: Stop making swap partitions—use swap files instead

#60

Post by blablabla123 »

williebeek wrote: post #46

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.

On the Desktop fine-grained partitioning is a bit questionable but on a server it's still quite practical. E.g. preventing the database or excessive logs from filling the disk space. The latter is also an attack vector actually.

Also generally swap is recommended on all systems. During normal use it should rarely be needed but if it's needed it prevents spurious crashes. E.g. make -j16 shouldn't result in a hard to comprehend crash because I miss 1 GB of RAM.

Post reply on HN