I installed Windows 7 on VMWare and it works just fine! However, when I leave the machine idling and work on my host OS, Windows 7 decides that it is a good idea to thrash disk and kill performance. How do I disable these background processes? Is it just indexer?
I'd first run sysinternals' procmon tool to see what is hitting the drive, or filemon. That should narrow down what process is first causing the disk thrashing, and from there decide what to do.
It is most likely a search index. If so, I'd try increasing RAM first of all to the VM if at all possible, then let it finish the indexing and it should be better after that. If that doesn't alleviate the issue then I'd start googling for how to turn off the search indexing on Win7. If you find with the sysinternals tools that it is most likely the search indexing causing issues then come back and ask about it (or see if it's already in SF or SuperUser) and see what solutions are available, as I'm right now assuming from the question that you need to find out what is causing excessive disk thrashing.
I had similar disk thrashing issues, I found that applying these tweaks it has calmed my disk thrashing a bit: Tweak settings in VMWare
- Disable "Take snapshots in the background"
- Disable "Restore snapshots in the background"
- Disable "memory page trimming"
- Create a separate virtual disk for the windows paging file
And of course disable windows search indexing in both the host and the guest OS.