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Re: Question about nmbclusters

Hi Greg,

many thanks for your message here.

Am Donnerstag, 23. Mai 2013, 08:04:16 schrieben Sie:
> So, the 16384 upper limit may be there because it's not clearly safe to
> go higher, and it's rare to need more clusters than that.
depends from usage... ;)

> On a system with known memory and workload, certainly you can tweak
> settings.  I'd try NMBCLUSTERS=32768 and see how that goes.
did that with NetBSD 5.x over several years without problems - will do that 
again now with 6. 
> Also, it's possible that you are having a leak.  Does this happen more
> after long uptimes?
this only occur's when much network connection load happens (as usual / 
possible on larger server systems).

> which will show the number of denied allocations.  Basically, watch
> "requests", "fail", and if requests-releases ends up higher and higher.
> One thing to keep in mind is that some network interfaces (e.g. bnx) use
> a vast number of clusters, because there are 512 receive slots and at
> idle each is filled with an mbuf cluster waiting for an arriving
> packet.  So a system with 8 bnx interfaces will have 4096 clusters used,
> when there is zero traffic.
use xennet interfaces only, but not know if that are affected too. In 5 i 
experienced a strange prob when using more then one interfaces in different 
networks - TCP was "scrumbled" / "hanging" on that further networks (reported 
here before).

many thanks for the hints!
best regards,


 Niels Dettenbach
 Syndicat IT & Internet

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