Running out of swap space????

[pauls at utdallas.edu]

I've got a server that is running out of swap space:

+pid 37308 (mysqld), uid 88, was killed: out of swap space
+swap_pager: out of swap space
+swap_pager_getswapspace(1): failed

The strange this is, this server has a 6GB swap partition!

swapinfo -h
Device          1K-blocks     Used    Avail Capacity
/dev/da0s1b       6291456     2.6G     6.0G    43%

This isn't exactly a resource-starved machine either:

CPU: AMD Opteron(tm) Processor 244 (1793.88-MHz K8-class CPU)
  Origin = "AuthenticAMD"  Id = 0xf5a  Stepping = 10
 
Features=0x78bfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,MMX,FXSR,S
SE,SSE2>
  AMD Features=0xe0500800<SYSCALL,NX,MMX+,LM,3DNow+,3DNow>
real memory  = 2146893824 (2047 MB)
avail memory = 2065797120 (1970 MB)
ACPI APIC Table: <PTLTD          APIC  >
FreeBSD/SMP: Multiprocessor System Detected: 2 CPUs
 cpu0 (BSP): APIC ID:  0
 cpu1 (AP): APIC ID:  1

FreeBSD hostname.utdallas.edu 6.0-RELEASE FreeBSD 6.0-RELEASE #0: Thu Mar 
30 19:25:18 CST 2006 
root at hostname.utdallas.edu:/usr/obj/usr/src/sys/SMPKERNEL  amd64

last pid: 52327;  load averages:  0.45,  0.46,  0.45 
up 11+03:42:04  03:32:15
63 processes:  1 running, 62 sleeping
CPU states:  5.3% user,  0.0% nice,  0.8% system,  3.9% interrupt, 90.1% 
idle
Mem: 1410M Active, 126M Inact, 190M Wired, 82M Cache, 214M Buf, 78M Free
Swap: 6144M Total, 2687M Used, 3457M Free, 43% Inuse

Any suggestions are welcome - what could cause this?  How to troubleshoot? 
Possible solutions/workarounds?

Paul Schmehl (pauls at utdallas.edu)
Adjunct Information Security Officer
The University of Texas at Dallas
http://www.utdallas.edu/ir/security/