Is there a limit to the size of swap (file or partition) I can have on my Linux machine? I know since it is a 32-bit architecture I can only have a file up to 4GB (so I know even if Linux allowed me to have a huge swap file 4GB is the limit if there is no other kernel limits) Anyone have any insight to this?
I search google and came across a bunch of posts regarding this and some said 2GB but all the posts were old and not from a trusted source.

There is no limit.. but if your going to be using this as a desktop.. I never exceed 200 megs for swap.. there's really no reason to use more as it won't be used ever or rarely, if it does get used constantly, that just means your RAM isn't doing its job efficiently.
For servers, just all depends on what kind of load your going to have, but just like a desktop, if your server ever hits swap in most cases, means there is something wrong or you need more RAM.

PS. Old rule of thumb, create your swap double the size of the amount of RAM you have.. but if you have 256 or more.. I wouldn't exceed 256mb for it.. unless its a server, etc.

A swap partition is only really useful if you have little memory (or an old box) or are doing a lot of memory intensive work.

If you have 256mb or more, you really don't need a large swap partition. Using the swap is normally a sign that your memory can't cope.

Why do you need such a large partition?

We have a cluster and each node has dual processors and and 1GB of RAM, that is no where near enough -- and the current swap is 2GB, but we are upgrading the RAM to 3GB or 4GB and need to increase the swap too... Since the datasets we use in our mpi application get to be huge and will max out the memory (and occasionally if numerous mpi applications are running need to do some swapping which is fine since it won't happen to terribly often). This application is used to running on a Cray X1 which can have 32768GB of RAM which I don't think Linux will allow so I was just curious if we could allocate 8GB of swap or if we have to create 4 seperate 2GB swap (partitions or files)...

Like mentioned above as this info was not mentioned.. there is no limit to swap.. at least not with the later kernels.

Great thanks!