Do I need a swap?

[gregwalton]

I'm trying to install Feisty beta in VirtualBox on an XP machine. The installer falls over every time it gets to partitioning, saying that it cannot format teh swap partition. I've given it a single 8GB virtual drive and I'm asking it to partition and format the drive as it wants (default).

The machine has 2GB of RAM, of which I could give 1.5GB to the Feisty model. With this much RAM it would never actually *need* a swap. My question is: can Kubuntu be installed with no swap partition - just everything in the root partition?

If it does need a swap partition am I better giving it another virtual drive for it or could I pre-partition and format root and swap in the 8GB using something like a GParted Live CD?

Any help appreciated

Greg

[gregwalton]

Re: Do I need a swap?

OK, back home now. I booted from an iso image of BOOTIT NG and partitioned the drive. Then I booted into the Feisty iso and it's now installing, having set up the formats and mount points in the installer.

[sky]

Re: Do I need a swap?

Hi,

In fact, your swap will be used only if you don't have enough ram... The result of too much ram used is that if it will full, your computer will crash

[gregwalton]

Re: Do I need a swap?

I realise that, thanks. What I wanted to know was if Kubuntu will work if you don't assign it a swap partition. The installer seems to insist on one, saying that at a minimum you need root and swap.

I'd still be interested in an answer as I intend to install Feisty on my 2GB RAM machine and it would be helpful for multibooting if I could just put it all in one primary partition.

No biggy, just interesting.

[penguin.ch]

Re: Do I need a swap?

Part of an answer at best, but maybe useful anyway ...:

http://www.penguin.ch/dokuwiki/doku.php/debianarted#remarks_on_swap

[gregwalton]

Re: Do I need a swap?

Thanks for that, UnicornRider. Using a swap file, rather than a swap partition might be a solution. It has the advantage that the disk heads will not have to move so far between the system and the swap.

I've been doing a bit of googling on the subject and it seems that Linux will potentially work better with a swap partition (or file) no matter how much RAM you have. It's hard to be absolutely sure this is not out-of-date now but it seems that Linux can only clear out certain types of RAM pages by using a swap space, so it is worth having one. This allows the RAM to be used more efficiently for both apps and disk buffers.

I found some test results that back this up, but they were using 2.4 kernels. I even found an experiment where a guy had managed to allocate part of his RAM as a swap space and the results were the best of all! The only time a swap show no advantage is when your RAM is bigger than all your application need plus the amount of disk space you are accessing.

If this need for a swap space is still the case with modern kernels it suggests they are a bit behind the times - more than 1GB of RAM is not that unusual these days.

Interesting stuff, though...

So I guess I will be setting up a swap, either as a file as suggested or maybe on a separate drive (the machine I'm using has over 700GB spread across three SATA drives). That way I can keep four primary partitions on my boot drive for multibooting.