Panic String: kmem_malloc(4096): kmem_map too small: 335544320 total allocated

[Aminuddin Abdullah]

I have 5 servers running almost at 70mbit/sec and each one of them will
crash/reboot after more than 24 hours. The most it can stay up is 48 hours.

How do I increase this memory from the default 320MB?

This is the log after the crash.

Dump header from device /dev/ad4s1b
  Architecture: i386
  Architecture Version: 2
  Dump Length: 2145722368B (2046 MB)
  Blocksize: 512
  Dumptime: Mon May 8 11:28:55 2008
  Hostname: XXX
  Magic: FreeBSD Kernel Dump
  Version String: FreeBSD 6.3-RELEASE #0: Wed Jan 16 04:45:45 UTC 2008
    root at dessler.cse.buffalo.edu:/usr/obj/usr/src/sys/SMP
  Panic String: kmem_malloc(4096): kmem_map too small: 335544320 total
allocated
  Dump Parity: 1828182091
  Bounds: 0
  Dump Status: good

Is there any option in version 6.3 to increase this?

My filesystem, df -h:

Filesystem     Size    Used   Avail Capacity  Mounted on
/dev/ad4s1a    496M     39M    418M     8%    /
devfs          1.0K    1.0K      0B   100%    /dev
/dev/ad4s1e    496M    228K    456M     0%    /tmp
/dev/ad4s1f    218G    1.3G    199G     1%    /usr
/dev/ad4s1d    2.9G    258M    2.4G     9%    /var

And fstab:
# Device                Mountpoint      FStype  Options         Dump
Pass#
/dev/ad4s1b             none            swap    sw              0       0
/dev/ad4s1a             /               ufs     rw              1       1
/dev/ad4s1e             /tmp            ufs     rw              2       2
/dev/ad4s1f             /usr            ufs     rw              2       2
/dev/ad4s1d             /var            ufs     rw              2       2
/dev/cd0                /cdrom          cd9660  ro,noauto       0       0


TIA