Both Canonical and Microsoft recommend enabling swap file for Ubuntu cloud images, even if you allocate plenty of RAM to the VM.
Any thoughts on that?
Modernizing Linux swapping: introducing the swap table
31–40 of 132 posts
Re: Modernizing Linux swapping: introducing the swap table
#32Earlier quoted context omitted.
I dont get why anti-swap is so prevalent in Linux discussions. Like, what does it hurt to stick 8-16-32gb extra "oh fuck" space on your drive. Either you're going to never exhaust your system ram, so it doesn't matter, minimally exhaust it and swap in some peak load but at least nothing goes down, or exhaust it all and start having things get OOM'd which feels bad to me. Am I out of touch? Surely it's the children wh…
The pro-swap stance has never made sense to me because it feels like a logical loop. There’s a common rule of thumb that says you should have swap space equal to some multiple of your RAM. For instance, if I have 8 GB of RAM, people recommend adding 8 GB of swap. But since I like having plenty of memory, I install 16 GB of RAM instead—and yet, people still tell me to use swap. Why? At that point, I already have the s…
You're mashing together two groups. One claims having swap is good actually. The other claims you need N times ram for swap. They're not the same group.
> Memory is limited either way; whether it’s RAM or RAM + swap
For two reasons: usage spikes and actually having more usable memory. There's lots of unused pages on a typical system. You get free ram for the price of cheap storage, so why wouldn't you?
Re: Modernizing Linux swapping: introducing the swap table
#33Both Canonical and Microsoft recommend enabling swap file for Ubuntu cloud images, even if you allocate plenty of RAM to the VM. Any thoughts on that?
Re: Modernizing Linux swapping: introducing the swap table
#34Earlier quoted context omitted.
I dont get why anti-swap is so prevalent in Linux discussions. Like, what does it hurt to stick 8-16-32gb extra "oh fuck" space on your drive. Either you're going to never exhaust your system ram, so it doesn't matter, minimally exhaust it and swap in some peak load but at least nothing goes down, or exhaust it all and start having things get OOM'd which feels bad to me. Am I out of touch? Surely it's the children wh…
The pro-swap stance has never made sense to me because it feels like a logical loop. There’s a common rule of thumb that says you should have swap space equal to some multiple of your RAM. For instance, if I have 8 GB of RAM, people recommend adding 8 GB of swap. But since I like having plenty of memory, I install 16 GB of RAM instead—and yet, people still tell me to use swap. Why? At that point, I already have the s…
The reason you're supposed to have swap equal in size to your RAM is so that you can hibernate, not to make things faster. You can easily get away with far less than that because swap is rarely needed.
Re: Modernizing Linux swapping: introducing the swap table
#35One pet peeve I have with virtual memory management on Linux is that, as memory usage approaches 100%, the kernel starts evicting executable pages because technically they're read-only and can be loaded from disk. Thus, the entire system grinds to a halt in a behavior that looks like swapping, because every program that wants to execute instructions has to load its instructions from disk again, only to have those ins…
I suffer from the same behavior, ever since I moved from Ubuntu to Debian.
An interactive system that does not interact (terminal not reactive, can't ssh in, screen does not refresh) is broken. I don't understand why this is not a kernel bug.
On my system, to add insult to injury, when the system does come back twenty minutes later, I get a "helpful" pop-up from the Linux Kernel saying "Memory Shortage Avoided". Which is just plain wrong. The pop-up should say "sorry, the kernel bricked your system for a solid twenty minutes for no good reason, please file a report".
Re: Modernizing Linux swapping: introducing the swap table
#36I'd like to see Linux gain support for actual memory compression, without the need to go through zram, similar to macOS/Windows.
zram has been "obsolete" for years, I don't know why people still reach for it. Linux supports proper memory compression in the form of zswap
Re: Modernizing Linux swapping: introducing the swap table
#37Earlier quoted context omitted.
You're implying that people are telling you to set up swap without any reason, when in fact there are good reasons - namely dealing with memory pressure. Maybe you could fit so much RAM into your computer that you never hit pressure - but why would you do that vs allocating a few GB of disk space for swap? Also, as has been pointed out by another commenter, 8GB of swap for a system with 8GB of physical memory is over…
I'm also in the GP's camp; RAM is for volatile data, disk is for data persistence. The first "why would you do that" that needs to be addressed is why volatile data should be written to disk. And "it's just a few % of your disk" is not a sufficient answer to that question.
Because of cost - particularly given the current state of the RAM market. In order to have so much memory that you never hit memory spikes, you will deliberately need to buy RAM to never be used.
Note that simply buying more RAM than what you expect to use is not going to help. Going back to my post from earlier, I had a laptop with 8GB of RAM at a time where I would usually only need about 2-4GB of RAM for even relatively heavy usage. However, every once in a while, I would run something that would spike memory usage and make the system unresponsive. While I have much more than 8GB nowadays, I'm not convinced that it's enough to have completely outrun the risk of this sort of behaviour re-occuring.
Re: Modernizing Linux swapping: introducing the swap table
#38One pet peeve I have with virtual memory management on Linux is that, as memory usage approaches 100%, the kernel starts evicting executable pages because technically they're read-only and can be loaded from disk. Thus, the entire system grinds to a halt in a behavior that looks like swapping, because every program that wants to execute instructions has to load its instructions from disk again, only to have those ins…
Linux swap has been fixed on Chromebooks for years thanks to MGLRU. It's upstream since Linux 6.1 and you can try it with echo y >/sys/kernel/mm/lru_gen/enabled
Re: Modernizing Linux swapping: introducing the swap table
#39I'd like to see Linux gain support for actual memory compression, without the need to go through zram, similar to macOS/Windows.
zram has been "obsolete" for years, I don't know why people still reach for it. Linux supports proper memory compression in the form of zswap https://wiki.archlinux.org/title/Zswap
Because I'd rather compress ram when running low on memory rather than swapping to my disks. zram is also default on some distros (e.g. Fedora).
Re: Modernizing Linux swapping: introducing the swap table
#40I'd like to see Linux gain support for actual memory compression, without the need to go through zram, similar to macOS/Windows.
I use zswap, which is a non-fixed intermediate layer between RAM and swap and worked great on my old laptop which had a max of 4GB RAM. Even use it now on my current 32GB laptop.
Full compression would be nicer, but I'd also like to see ECC emulation (or alternative) as a cheaper alternative to the real hardware, although with current prices that might be less so.