Significant memory usage

[Ondřej Surý]

> On 2. 7. 2025, at 0:14, OwN-3m-All <own3mall at gmail.com> wrote:
> 
> I wonder if other memory issues users are complaining about are related.

I don’t know. You were the first one to actually provided a reproducer and a usable test case. Despite your exaggeration about “countless” reports there were not that many of them actually.

> How many zones can a bind instance handle realistically?

Internally, we are testing BIND 9 with 1M small zones and it works just fine.

What happened was that 9.20 introduced a new database backend called QP that replaced venerable custom red-black tree implementation we had. The side effect of that was 12K memory chunk overhead per zone. Under normal conditions, this would not manifest as that 12K would get filled with the zone data, but in the case of almost empty zone, the memory chunk would be mostly empty and it just blew up the memory requirements.

BIND 9.22 will contain an optimization that gradually increases the memory chunk size and that allows “auto tuning” for both small zones, large zones and the cache.

Ondrej
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Ondřej Surý — ISC (He/Him)

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