Probably because you have enough swap (memory) to handle the larger mfs 
filesystem..

Just my two cents.

73 de AI8W, Chris

At 21:41 03-07-03, Steve Rumble wrote:
>On Thu, 3 Jul 2003 02:14:55 -0400 (EDT)
>der Mouse <mouse@Rodents.Montreal.QC.CA> wrote:
>
> > Is 247M anywhere near any of your per-process resource limits, by any
> > chance?
>
>         Apparently proc.curproc.rlimit.{datasize,stacksize}.{soft,hard} =
>268435456. These cannot be altered, neither increased nor decreased.
>sysctl takes values without complaint, however upon checking them again,
>they appear unchanged. This appears to hold true on both of my i386
>machines, where datasize.hard is set to 1073741824 on both the 64mb and
>1024mb machine with one and two gigabytes of swap, respectively.
>Although it's rather pointless to do so, the 64mb machine can mount a
>512mb mfs without issue.
>         Do you happen to know how datasize.hard is limited? Am I missing some
>understanding here? Meanwhile, I'll poke around the code to see what I
>can find.
>
>Thanks,
>-Steve

73 de AI8W, Chris