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Re: Question about nmbclusters



Am Mittwoch, 22. Mai 2013, 21:50:12 schrieben Sie:
> I am pretty sure you will need to compile this into a new kernel.
> I have used:
> options         NKMEMPAGES=98352
> options         NMBCLUSTERS=65568
hmmm,

the NetBSD nmbclusters topic seems confuse manies in similiar stuations.

According to:
http://www.netbsd.org/docs/kernel/#mclpool-limit
and Jörg Sonnenbergers hint's at:
http://www.sonnenberger.org/2010/02/11/dynamic-mbuf-cluster-limit/

It should be possible to change that value - since 6 or 6.1 at runtime and/or 
boot time and <6 by a kernel build option (requires recompilation).

I've changed to 6.1 and 6.99 even because of this feature. But the upper limit 
seems to be 16384 now which is very low on many productive internet systems / 
apps (i.e. with nginx, p2p nodes etc.)!

Is anyone her who culd bring some light into this topic? Why this "low" limit 
is still fixed in the kernel? Why it did not could be changed at i.e. runtime 
(as on other systems and NetBSD within a small window) or - at least - on boot 
time and a recompilation is required to get this limit up?

What side effects have a higher nmbclusters / mbuf setting?

It seems that FreeBSD allows a larger scale of nmbclusters settings during 
runtime then NetBSD and the amount of nmbclusters by default is calculated 
during boot relatively to available physical RAM.
http://rerepi.wordpress.com/2008/04/19/tuning-freebsd-sysoev-rit/

Settings of i.e. 65536 seem's not to be a problem.

hmm,

Many thanks for any light on this in advance,


Niels.
-- 
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 Niels Dettenbach
 Syndicat IT & Internet
 http://www.syndicat.com
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