[rbldnsd] Memory allocation questions

[Scott Knight]

Hello,

I am trying to get a better understanding of how
rbldnsd allocates memory – both on initial startup and
during a reload.

Our setup is as follows:

We use the ip4set format to load two separate zones. 
One zone is very small (~150K) and the other is very
large (i.e. > 400MB).  The majority of the entries are
individual, not consecutive IPs (/32's).

We also have the “-f” option specified so that rbldnsd
continues processing requests during a reload.

The system has 1GB of physical RAM and 1GB of swap.

We initially ran into an OS limitation where by a
single process was limited on the amount of memory it
could allocate.  This limit was set to 512MB, and a
445 MB zone file was running out memory while loading.
 We have gotten past that obstacle by increasing that
OS limit.

My questions revolve around the amount of memory
allocated however.  For example, once that 445MB file
was loaded completely, the amount of memory being used
dropped down to ~137MB.  So on initial startup, does
it allocate much more memory than might be needed and
then give it back after it’s fully loaded?

Also, how does this differ on a reload?  The example I
have is that I took an ~800MB file and put in place
while rbldnsd was already running (with the 445MB file
in memory).  The reload took place successfully and
the ~800MB was loaded.  However, I stopped the process
and restarted it, and the ~800MB file caused rbldnsd
to run out of memory.

So, basically, we are trying to find our “limit” and
trying to plan the system accordingly, but any insight
into the allocation process would be most helpful.

Thank you in advance,

SK


		
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