Re: Performance of DLZ skeleton

On 6.1.2015 01:00, Jorgen Lundman wrote:
>> Every query triggers a database lookup, and the response from the database
>> is in text format, which has to be marshalled into DNS wire format.
>> This all adds significant overhead to DLZ query processing, and is the
>> reason I don't recommend DLZ be used for high-traffic servers.  If you
>> need high throughput, use DLZ as a hidden master and have standard
>> BIND servers acting as slaves to answer queries.

Alternative is to use (non-standard-yet) API for database back-ends which
allows you to plug-in your own code directly into BIND's database API.

Patches are here:
https://github.com/spacekpe/bind-dynamic_db/commits/dyndb_bind9_9

The API is heavily used by:
https://fedorahosted.org/bind-dyndb-ldap/

The API itself is pretty low-level but also low-overhead:
bind-dyndb-ldap driver offers ~ 99 % read performance of plain BIND but at the
same time it immediately propagates changes from LDAP to BIND + supports DNS
dynamic updates from BIND to LDAP and DNSSEC in-line signing at the same time.

Petr^2 Spacek

> 
> We also tried some local caching with;
> 
> view "internal" {
>     # Allow localhost (forwarder) as well as L4 health checker
>     match-clients { 127.0.0.1; 172.20.11.2; 172.20.11.3; 172.16.12.2; };
>     recursion no;
>     allow-recursion { any; };
>     zone "localhost" { type master; file "localhost.zone"; };
>     dlz "ldap zone" {
>     database "ldap 20 v3 simple DLZmagichere
>     };
> };
> 
> view "external" {
>     recursion yes;
>     allow-recursion { any; };
>     max-cache-size 512M;
>     forwarders { 127.0.0.1; };
>     forward only;
> };
> 
> 
> But we also patched BIND to set authoritative reply from the cacher, and
> allow recursion for external. It works well for us.
> 
> Lund


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