[Unbound-users] unbound should probably manage other RLIMITs as well...

[Greg A. Woods]

At Wed, 28 Oct 2009 09:02:31 +0100, "W.C.A. Wijngaards" <wouter at NLnetLabs.nl> wrote:
Subject: Re: [Unbound-users] unbound should probably manage other RLIMITs as well...
> 
> Note it is useful to also increase the message cache size -
> you have been using 256m to store rrsets which helped recursion
> but not answering clients from cache.  msg-cache-size: 128m.

I'm not sure I understand.  What is the relationship between the
msg-cache-size and the rrset-cache-size?  They seem to default to being
the same size, but I thought that was just a co-incidence.

I'm not even sure what msg-cache-size is used for.  The documentation
for msg-cache-size just says, very unhelpfully:

    "Number of bytes size of the message cache"

The on-line "how to optimise" page gives the rule you suggest, but also
without any explanation:

    "Use roughly twice as much rrset cache memory as you use msg cache
     memory."

I have assumed, perhaps wrongfully, that the msg-cache is simply the
size of the cache for messages that have been received from clients and
upstream nameservers but not yet parsed and handled.  I'm guessing it
could be used to format replies to be sent to clients too.  I'm not sure
why it would be useful for it to be up to 1/2 the size of
rrset-cache-size.

If there is such a fixed relationship, then should it not be encoded
into the controls heuristics such that the user need only specify one
value for sizing the caches?

I wish I had time to learn the code!

-- 
						Greg A. Woods
						Planix, Inc.

<woods at planix.com>       +1 416 218 0099        http://www.planix.com/
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