Hi Anand,

the estimate highly depends on the zone contents of course,
the estimate seems like a good upper bound.
I remember measuring about 500MB (signed) zone and it yielded about 1.3G as well,
but the virtual memory was at about 2G due to how memory allocation works.
So it's not entirely clear what essentialy IS used memory and what is just waste or kept.

The best course of action would be to write a tool that is able to make better estimate
based on the zone file, would that be okay?

Cheers,
Marek

On 7 June 2013 13:13, Anand Buddhdev <anandb@ripe.net> wrote:
Dear Knot developers,

I'm testing Knot 1.3.0-rc1 now. One of the things I'd like to be able to
do is to estimate Knot's memory usage without actually loading all my
zones into it (because if it runs out of memory it will be killed).

One very crude way was to load a single zone from a plain text zone
file, and comparing the memory used by knot with the size of the zone on
disk. For a zone of size 229MB, knot is using about 1.3GB of RAM. So I
could say that knot wants about 6x as much RAM for each zone. Is this a
reasonable asumption?

Alternatively, since you know how knot uses memory for a zone, are you
able to provide a small program which can read zones one at a time,
calculate the RAM required for each zone, and then print a summary of
the total RAM required to load all those zones into knot?

We frequently get questions from our users along the lines of "I'd like
you to slave this new zone" or "we are going to sign this zone; will
your server be able to load it?" It would help an operator immensely if
he can get an estimate of the additional RAM required.

Regards,

Anand Buddhdev
RIPE NCC
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