Re: Question about nmbclusters

[yancm <yancm%SDF.ORG@localhost>]

On 2013-05-22 19:07, Konrad Neuwirth wrote:
> Hello everyone,
>
> we are currently facing severe problems with nmbclusters on a NetBSD
> 6.0 generic system (amd64). We're running short of nmbclusters, and I
> do not understand how I can increase them.
>
> sysctl kern.mbuf.nmbclusters
> kern.mbuf.nmbclusters = 16384
>
> I see that this number is both derived at boot time (writing another
> value into the kernel has no effect), but I also cannot turn that
> knob. The only value that doesn't lead to an 'invalid argument' error
> is 16384. I have no idea what a better value is, but we've outages of
> up to ten minutes that take down all network interfaces on that 
> system
> (and we're at six networking interfaces, one with three vlans -- and
> they're mostly well-used).
>
> So: What can I do to get that value up, to make the system more 
> stable?
>
> Thank you,
> Konrad

I am pretty sure you will need to compile this into a new kernel.
I have used:
options         NKMEMPAGES=98352
options         NMBCLUSTERS=65568
in my kernel config file in the past...pretty sure I remember it not 
being configurable at runtime.

The actual number used is of course up to you and the system resources 
you have available.

--gene