Do you use a swapfile, swap partition, or neither?

Trademark97

Which one do you use? If you use either a swapfile or swap partition, why did you choose that particular swap method? If you don't use either, why did you decide not to use swap?

Personally, I've been using a swapfile for easier resizing (I use XFS as my filesystem and so resizing is tricker than it would be otherwise).
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spica · Guru Joined: 04 Jun 2021 Posts: 329

There's no Neither option in the poll.
IMO with 16+ RAM the swap only does a wear to SSD.
Swapfile can be turned on any time if the question is a lack of RAM.
Those who want "hibernation to swap" they obviously use a partition.

APolozov · Posted: Sat Jan 28, 2023 8:23 am Post subject:

I am using a swapspace (dynamic swap manager) + zswap kernel option.
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NeddySeagoon · Posted: Sat Jan 28, 2023 9:48 am Post subject:

Trademark97,

I use both :) but I suppose the real answer is neither.

If I plan ahead I use a partition, or actually a swap logical volume.
When i need swap for diagnostics, its a swap file, as its only for the duration of the diagnostics.

The kernel uses the partition/logical volume raw, there is no filesystem code involved.
A swap file is marginally slower as all the IO has to go through the filesystem layer.

My main system has 128G RAM because I don't plan to upgrade it, so it does not need swap today. I don't use hibernate.
In 10 or 12 years, memory requirements will grow, as they always have, so I may need to add swap within the lifetime of this system.
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pa4wdh · l33t Joined: 16 Dec 2005 Posts: 881

I use swap partitions by default. For sizing i usually choose a sensible amount based on the system's real memory and amount of storage available. For my desktop this means it has the same amount of swap as memory, my Raspberry Pi has more swap than memory.
If i somehow need to expand swap during the lifetime of the system (which so far has never happened) i'll use LVM where possible or a swap file when LVM is not available.
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asturm · Developer Joined: 05 Apr 2007 Posts: 9262

file. I have stopped obsessing over the ideal partitioning layout years ago when SSDs arrived.

AJM · Posted: Sat Jan 28, 2023 11:56 am Post subject:

I want to vote neither but there's no option for that (I want to make a political joke here but will refrain!)

If I have a memory constrained system I just use enable a swapfile as required but have got on far better without swap for years now (since RAM became so relatively cheap.) My laptop has a swap partition for hibernation purposes.

Suicidal · l33t Joined: 30 Jul 2003 Posts: 959 Location: /dev/null

I have a partition configured, but I also have 32 GB of ram. I’ve never seen it get used, even in an emerge -e @world with MAKEOPTS=“-j25 -l22”

mv · Watchman Joined: 20 Apr 2005 Posts: 6780

swap partition + zswap + (sometimes for a part) zram/swap with a lower priority.

I have only 8GB, so ram is an issue for large projects even with -j3. Sometimes I experienced a slight performance improvement when adding a small amount of zram in a lower priority swap partition, sometimes I think that I had actually bugs with it (or with the combination with zram?), so I sometimes toggled the state.

steve_v · Guru Joined: 20 Jun 2004 Posts: 409 Location: New Zealand

Swap partition + zswap. earlyoom too, because linux handling of memory pressure under interactive workloads still blows, and a notification on the desktop to the effect of "low memory, killing process xyz" before the system slows to a crawl is kinda nice.
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Anon-E-moose · Posted: Sat Jan 28, 2023 4:39 pm Post subject:

Don't have any swap set up, 64g mem at the moment, plenty for my uses without a swap.

BUT if I had to use a swap, I'd set up a file on my nvme, while I might lose a little performance with file vs partition,
since I'd be using an nvme that's not much of a concern.
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apiaio · Guru Joined: 04 Dec 2008 Posts: 426

I use swap partition, but I believe, that it has never been used.

Gatsby · Posted: Sat Jan 28, 2023 6:38 pm Post subject:

Swap partition + swap file.
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mrbassie · Posted: Sat Jan 28, 2023 7:22 pm Post subject:

I've voted partition but it's really zram and a zvol (I know you shouldn't do the latter, but I did and I can't be arsed to repartition. I've 16 gigs of ram and it's an 8/8 split. It's a cludge but it's it's not as crap as it was with just the zvol).

sublogic · Posted: Sun Jan 29, 2023 3:11 am Post subject:

On an old laptop, swap and hibernation to a logical volume. And zswap. The poor thing has only (hah!) 1GB of RAM. ionice -c idle is your friend.

On my desktop, swap to LVM also. 32 GB on that one, so

szatox · Advocate Joined: 27 Aug 2013 Posts: 3420

My system is on LVM, so I guess neither.
Stable diffusion can get really hungry cranking those pics

eccerr0r · Posted: Sun Jan 29, 2023 3:40 am Post subject:

Both, depending on machine and situation. I tend to use files recently so it's easier to manage them but a little harder to resume from (for hibernation).

I think LVM volumes easily qualify as 'partition' for most intents and purposes, except for resume from hibernation...
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allistarM · Tux's lil' helper Joined: 22 Jul 2004 Posts: 141

I normally don't use either because I have 64Gb of RAM. However, when running IntelliJ x 2 and compiling Chromium it can run out of memory, so I add 32Gb of swap space via a swap file which is on a RAID 10 spinning disk array.

gtwrek · Posted: Mon Jan 30, 2023 3:29 pm Post subject:

Swapfile, turned on, only when I need it (i.e. during world updates). 16 GB physical RAM. No real reason swapfile vs partition, other than I didn't expect to need swap at all when I setup my partitions. But emerging GCC, LLVM, Rust, and chromium (amongst others) starting getting more and more memory hungry... So added a swapfile, and "swapon; emerge; swapoff" in my portage update flow. The swapfile is on my large spinning rust disk.

eccerr0r · Posted: Mon Jan 30, 2023 4:14 pm Post subject:

For those who "turn swap on when doing big jobs" -- I don't understand why. I just leave swap on all the time whether I need it or not. I don't have gobs of memory, but most of the time when I'm not building big packages, I don't need the swap (other than for hibernation) but I leave it on all the time.

It's a "just in case" - there when I need it, don't need to think about it, it's there, ready.

Just trying to dispel the myth that swap is bad even when you have gobs of memory... it's not a bad thing, and great for sloppy software programmers these days that leak memory.
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asturm · Developer Joined: 05 Apr 2007 Posts: 9262

^exactly that.

gtwrek · Posted: Tue Jan 31, 2023 12:25 am Post subject:

pjp · Administrator Joined: 16 Apr 2002 Posts: 20484

steve_v · Guru Joined: 20 Jun 2004 Posts: 409 Location: New Zealand

eccerr0r · Posted: Tue Jan 31, 2023 5:32 pm Post subject:

Actually simply "needing" swap is not a bad thing either, swap is only bad if there's barely enough to do what the computer needs to do and start thrashing. But this is not the fault of swap - it's the fault of the user trying to use more than what's feasibly available.

Again memory leaks is a big problem. You use memory and you leave it in there without regard to really needing it in there (even if you keep track of it, the mere fact you're occupying ram and not using it is the problem), and even worse - forget that you had it there. All of this data can be swapped out and memory reclaimed for active use which will improve performance.

Forcing the computer to swap text pages is the absolute worst thing to let the computer do. There aren't that many of them as a percentage of all pages, especially when compiling/linking and hence that's why computers tank when you run out of memory and no anonymous swap is available.
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