On 19/10/2019 16:24, Mick wrote:
On Saturday, 19 October 2019 14:11:26 bstmad.scientist.at.la...@tutanota.com
wrote:
Do systems run different memory management when swap is on versus no swap?
The answer to this question is an unqualified yes, although you do not define
your meaning of "different memory management". The existence of swap space
and the kernel's swappiness setting will change the way memory is dynamically
allocated to processes at runtime and may affect the responsiveness of your
system.
Memory management was massively rewritten roundabout kernel 2.4.
The original swap algorithm NEEDED twice ram as swap. And when Linus
ripped out all the "optimisation", the vanilla kernels only needed to
touch swap, and if they didn't have twice ram they would crash.
At that point, the recommendation changed to "no swap is fine, twice or
more is fine, just don't have swap less than twice ram".
My personal rule is to take the motherboard's max ram, double it, and
create a swap partition that size on every disk. So my current desktop
system has 80GB of ram/swap - 4x4GB slots times 2 disk drives. And my
new system has 4x8GB so that'll be 160GB!!! HOWEVER - Richard Brown of
SUSE said that's dangerous - if somebody fork-bombs you it'll take a
long time to fill that much swap and regaining control of your system
could well be a big red switch job.
Cheers,
Wol
