Swap files becoming a real problem. How to manage???

Hi Brad DeMoss;

You can do any or all of the following to reduce swap files.

If you don't have 2 GB of RAM, increase RAM to 2 GB.
Replace disk drive with a larger disk.
Reduce the amount of work you are doing.

Allan

I can confirm seeing similar behaviour using Apple Mail. Mind you, I was deleting around 6000 messages on a single delete-key-press (and so I was expecting some pain), but while "writing changes to disk" I watched /private/var/vm climb up to 18 swap files (using MenuMeters and keeping the memory menu open).

I am wondering if there are any new "larger" built in limits for NSUndo?

Brad DeMoss wrote:
I have an 80 GB MacBook Air that is constantly filling up with swap files. I recently had to restart the machine to free up 32 GB of space.

Are you actually seeing 32 GB of hard drive space used by swap files on the drive -- or just going by the "VM size" displayed in Activity Monitor? If the latter, don't worry about it. On my iMac with a total of 169 GB of its HD used, my "VM size" is a whopping 120 GB. Yet /private/var/vm contains only one swap file (swapfile0), using a mere 64 MB (binary base, reported as 67.1 MB in Snow Leopard's decimal based system) of HD space.

"VM size" isn't what you might think it is: it measures the total of how much memory address space is allocated to each process, not the total of how much real or virtual memory each is actually using. The OS creates swap files as needed to handle the necessary VM swaps, & swaps chunks (called pages) of any existing one with real memory without creating a new VM swapfile when it can. (It always creates at least one.) But it only creates new swap files when it must swap out more than it can from the existing ones. So from my swapfile size, I know that since startup the OS has never had to page out more than 64 MB at a time. If it did, it would create swapfile1, which probably would be 64 MB too: although I can't remember the details, the OS is programmed to create new swap files in some sequence like 64 MB, 64 MB, 128 MB, 256 MB, etc. -- whatever the VM designers decided would be the best compromise between efficiency & disk space use.

It is true that the swap files remain & continue to take up HD space until a restart, but they are relatively tiny, at least unless you are using apps that actually require massive amounts of paging to occur.

FWIW, MenuMeters is a SystemUIServer plugin (also known as a Menu Extra). Apple does not support third party Menu Extras, which can destabilize the OS if not written carefully, so makers of things like MenuMeters rely on MenuCracker or its equivalent, which is basically a hack of the OS.

IOW, when you use MenuMeters, you are not using the OS supplied by Apple but instead a hacked variant that may or may not act like the Apple-supplied version. If you experience stability problems, especially after applying a system update, this is one of the first things to look for, since this kind of hack is often broken when Apple changes the OS.

One possibility that occurs to me is that you have an application running that has a memory leak (or some other memory allocation bug). That is it keeps allocating chunks of memory and never frees memory when it is no longer needed. In this case running doesn;t require that you be actively doing something with it.

What happens if you let it run over night with without Safari or Entourage or any other App running.

Steve