Re: Tunning FreeeBSD and PostgreSQL

Vivek Khera wrote:
> >>>>> "SH" == Stephen Howie <showie@centwire.com> writes:
>
> SH> Richard-
> SH> That was very helpfull Thanks!
> SH> I still would like some guidance on tunning FreeBSD (shmmax and shmmaxpgs).
> SH> Do I need to even touch these settings?
>
> Here's what I use on FreeBSD 4.7/4.8.  The kernel settings don't hurt
> anything being too large for the SHM values, since they are limits,
> not anything pre-allocated (from my understanding).  These settings
> allow for up to 100,000 shared buffers (I currently only use 30,000
> buffers)

I think the only downside to making them too big is that you allocate
page tables and prevent that address range from being used by other
processes.  Of course, if you have much less than 4 gigs of RAM in the
machine, it probably isn't an issue.

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