I would not worry too much about the kernel parameter change.
Systems with such low values will need those parameter changes for most
other databases too (since they all use SYS V shm).
Installations where the administrator is not involved will most likely be test/university
installations, where memory is usually sparse anyway (buffer increase not wanted).
I would not change to mmap if that would actually require a file on some systems.
(systems with Gb of RAM are starting to gain ground is only one argument)
Andreas
> I am going through my mailbox and I believe we never found a portable
> way to allocate shared memory other than system V shared memory.
> Increasing the amount of buffers beyond a certain amount requires a
> kernel change.
>
> Has anyone come up with a better way?