Virtual Memory/Swap file size?

**kairi00** · September 3rd, 2001, 07:19

Hope this thread actually belongs here... anyways, here goes.

When you install Linux/Solaris, you're usually asked to create a swap partition, and the recommended size is twice the amount of RAM that you have. My question is: why twice the size? What's the reasoning behind this magic number? What would happen if it's more/less than 2x the RAM you have?

If anyone can give me a detailed technical explanation on this, I'd greatly appreciate it.

Thanks!

__________________
"Not every ejaculation deserves a name."

--- George Carlin

**Xeven** · September 3rd, 2001, 07:49

I guess this rule came about when in the old days people only < 8 megs of RAM and OS's needed more memory to run. So it was a rule of thumb to use 2 or 2.5x times the available physical memory as the swapfile size [read this from somewhere]. But nowadays,
RAM is pretty cheap, and putting < 64 Megs on your PC is quite disturbing.., so the swapfile size only matters if your running lots of applications that take lots of ram at the same time..., but I guess old habits die hard, and people are still sticking to the 2x rule. Sorry I know the post isn't "technical" ....

__________________

**kairi00** · September 3rd, 2001, 21:27

Ah thanks for the answer. That partially answered it, though I still have this big question: why the number 2? They must've come up with it somehow.... oh well

Thanks again

__________________
"Not every ejaculation deserves a name."

--- George Carlin

September 3rd, 2001, 07:19	#1
kairi00 Puchiko-nyu! Join Date: Jul 2001 Location: 49° 11' N 123° 10' W Posts: 2,853	Virtual Memory/Swap file size? Hope this thread actually belongs here... anyways, here goes. When you install Linux/Solaris, you're usually asked to create a swap partition, and the recommended size is twice the amount of RAM that you have. My question is: why twice the size? What's the reasoning behind this magic number? What would happen if it's more/less than 2x the RAM you have? If anyone can give me a detailed technical explanation on this, I'd greatly appreciate it. Thanks! __________________ "Not every ejaculation deserves a name." --- George Carlin

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September 3rd, 2001, 07:49	#2
Xeven A BIG BAD BATARD™ Join Date: Sep 2001 Posts: 5,568	I guess this rule came about when in the old days people only < 8 megs of RAM and OS's needed more memory to run. So it was a rule of thumb to use 2 or 2.5x times the available physical memory as the swapfile size [read this from somewhere]. But nowadays, RAM is pretty cheap, and putting < 64 Megs on your PC is quite disturbing.., so the swapfile size only matters if your running lots of applications that take lots of ram at the same time..., but I guess old habits die hard, and people are still sticking to the 2x rule. Sorry I know the post isn't "technical" .... __________________

September 3rd, 2001, 21:27	#3
kairi00 Puchiko-nyu! Join Date: Jul 2001 Location: 49° 11' N 123° 10' W Posts: 2,853	Ah thanks for the answer. That partially answered it, though I still have this big question: why the number 2? They must've come up with it somehow.... oh well Thanks again __________________ "Not every ejaculation deserves a name." --- George Carlin