As far as I know, it won't be stable at all, if you get it to work at all.
The required hardware is a 233 megahertz G3 processor and above. Even with an early iMac, an early Power Macintosh G3, or an early PowerBook G3, the system runs quite slowly.
I am not saying that it's not possible. What I am saying is that it isn't going to be very fast, if it works at all.
To run Mac OS X Server, I'd reccomend nothing less than a Power Macintosh 8600/9600 with a lot of RAM.