I had a pretty major crash the other night when I was doing a stress test of my vbulletin forum (it's really the only thing running at this time, and I was up to 32 users online at the same time)

I have a Raq4i, with 128MB RAM. I would have thought that would have been enough to handle this kind of load. I had a TOP window up and running, and it was cruising along pretty good. When I got up to 32 users on the board, the cpu/memory resources spiked, and everything locked up (required a reboot of the server). When I logged at the error log (httpd), here is what it said at the time of the crash

FATAL: erealloc(): Unable to allocate 61440 bytes
FATAL: erealloc(): Unable to allocate 122880 bytes
FATAL: emalloc(): Unable to allocate 256 bytes

I'm not sure what the processes erealloc and malloc do, but does this point to a 'out of memory' problem? Again, I thought since this thing can handle a 'couple hundred' virtual domains, 128mb would have been enough for 32 users on a single vbulletin forum with nothing else running.

Any thoughts? Thanks in advance.

Most likely a coding bug. Erealloc is used to relocate memory objects -- PHP is know to have problems with this. Might want to check out the Vbulletin forums for more info. Also, 128MB of RAM is not a lot -- consider 256MB -- also monitor how much memory you have unallocated during the stress test. My guest is this is a programming issue involving a bad call to eralloc.

Also (someone *please* correct me if I'm wrong!), running top is a bit of a resource sucker.

Certainly correct RE: Top. Its a resource hog++ as its obviously tracking processes in realtime - thus becoming a heavy burdon itself!

moz.

I use uptime, I even have it called from a refreshing php script so I can check the serverload for a while without telnet. I can let the script mail me when the load gets to high.
I think I'll run it every 5 minutes so it can shutdown the webserver when the serverload gets to high and start the webserver again when the load is normal :cool:

Okay, so any other suggestions for monitoring server load in real-time that doesn't consume a bunch of resources?

I put in an order to upgrade the memory to half a gig.

Install http://phpsysinfo.sourceforge.net/