Hi,
I’ve searched for a recomendation about swap space sizing in SLES but I haven’t found anything.
I’m working with SLES 11 and SLES 12.
Anyone have a recomendation about this theme?
Thanks
Hi
How much system ram? Since it’s a server your not going to
hibernate/suspend little point in have a swap around 1~1.5 installed
RAM.
–
Cheers Malcolm °¿° LFCS, SUSE Knowledge Partner (Linux Counter #276890)
SUSE Linux Enterprise Desktop 12 GNOME 3.10.1 Kernel 3.12.32-33-default
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[QUOTE=malcolmlewis;25916]Hi
How much system ram? Since it’s a server your not going to
hibernate/suspend little point in have a swap around 1~1.5 installed
RAM.
–
Cheers Malcolm °¿° LFCS, SUSE Knowledge Partner (Linux Counter #276890)
SUSE Linux Enterprise Desktop 12 GNOME 3.10.1 Kernel 3.12.32-33-default
If you find this post helpful and are logged into the web interface,
please show your appreciation and click on the star below… Thanks![/QUOTE]
System RAM size is variable.
The minimum size for my servers is 4 GB and the maximum is 64 GB.
In the case of big RAM sizes I think that use 1~1.5 swap space size is a waste of disk and that’s the reason that I was searching for a recomendation.
Thanks
Hi
Well then it depends on the system load with the lower sizes of ram,
but you can’t really tell until you monitor and see if it swaps…
I have 8GB in my systems (laptops and a SLES 12 server) I wind down the
swappiness so it will use ram before looking to swap.
vm.swappiness=1
vm.vfs_cache_pressure=50For the 4GB systems probably 1-1.5 times anything greater than 16GB I
probably wouldn’t worry unless you have the occasion for a runaway
process, then having swap sometimes helps to get to a system before it
goes belly up…but again that is all based on your observations of the
systems.
You can always add a swap ‘file’ if needed, then there is the zram
kernel module.
–
Cheers Malcolm °¿° LFCS, SUSE Knowledge Partner (Linux Counter #276890)
SUSE Linux Enterprise Desktop 12 GNOME 3.10.1 Kernel 3.12.32-33-default
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Yeah, and in my own systems I basically set swap at 2 GiB regardless. My
laptop, this time, has as much as it has RAM for hibernate reasons, but
for the last five years or so I ran without swap at all. It’s not
necessary, and my personal experience with it is that at best it delays
the inevitable. If you have a runaway process (vs. a slow leak) then
consuming however much swap you have is not going to take very long, and
in the meantime your system’s performance will be terrible. In most cases
I’d rather have the process die so that the system still responds and I
can start investigating why the process died. The alternative is a lot of
terrible performance for whatever is on the system, and if virtualizing
then probably for everything else on the virtual host, for no real benefit
since all you’re going to do to fix it is kill the lousy process anyay.
Anyway, 2 GiB just in case you need some extra memory, but not so much
that your box wastes tons of time in the runaway case… just let those
things die and start fixing the heart of the problem (the process).
–
Good luck.
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