Wise disk parting.

[Steve Lindemann]

Mikkel L. Ellertson wrote:
> Steve Lindemann wrote:
>> In days gone by the rule of thumb for *nix was swap should be 1/2 the
>> size of RAM.  Hadn't heard about that rule changing, but then I'm not on
>> the bleeding edge these days....  though on my servers with 16GB of RAM
>> it felt like a bit much setting swap to 8GB (but I did it anyway 8^)
>>
> I though the old rule was to for swap to be 2x RAM. This was because
> a core dump would use 1x RAM size of swap. This is no longer the
> case. Now days, if you are doing suspend to disk, you need slightly
> more then the amount of RAM in swap space, plus what you need for
> normal operation. If you are not going to suspend to disk, then the
> swap space needed depends on the system. If you have enough RAM, you
> do not need any swap space. For example, this system has 1M of RAM,
> and it normally uses more then 5M of swap space. There are no simple
> rules for swap size any more.
> 
> The thing to remember is that swap space is used for when you do not
> have enough physical  memory. It is sometime used for keeping
> program that are sleeping handy for reloading, but still freeing up
> RAM for other uses. (A program may get swapped out when more RAM is
> needed, and left swapped out even though there is RAM being used for
> buffers...)
> 
> Mikkel
> 
hhhmmm.... now that you mention it, I do remember way *way* back using 
2x RAM for swap.  But we were lucky to a 1MB of RAM back then, 256K and 
512K was pretty common in the big servers.  Somewhere along the way, as 
RAM size increased, I picked up the 1/2 RAM rule of thumb (probably when 
we passed the 1MB mark) and it's worked ok for me for some while now so 
I pretty much forgot about the 2x rule of thumb.   I wish I could blame 
old age, but I've pretty much always had a rotten memory (probably could 
use some swap space of my own  8^)
--
Steve Lindemann                         __
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