Contacts
IBSurgeon

Optimized Firebird configurations

A collection of optimized Firebird configuration files for common performance problems. Prefer the Configuration Calculator for current setups; the downloadable files below are mainly for reference and for outdated Firebird versions.

Firebird 3 (reference downloads)

These files are kept for reference. For new or updated Firebird 3 deployments, prefer the Configuration Calculator. If you still want a static file, select the architecture below.

SuperServer

Choose SuperServer if you have one main database and, optionally, 2-5 smaller (less loaded) databases on the same server. Configure each database in databases.conf.

SuperClassic

Choose SuperClassic if you have many databases on the server (about 10 to 1000), they are roughly equal in load, and your application is stable (no “Abnormal termination” messages in firebird.log). SuperClassic usually gives better control of sorting memory and performance than Classic.

  • RAM 8-12 GB · 10+ databases · up to 150 connections in total · 64-bit only firebird.conf
  • RAM 16-32 GB · 10+ databases · up to 300 connections in total · 64-bit only firebird.conf

Classic

Choose Classic if you have many databases (about 10 to 1000) that may be unstable, or if you use 32-bit UDFs.

  • RAM 8-12 GB · 10+ databases · fewer than 150 connections in total 32-bit · 64-bit
  • RAM 16-32 GB · 10+ databases · fewer than 300 connections in total 32-bit · 64-bit

Firebird 2.5 (reference downloads)

These files are kept for reference and older deployments. For Firebird 2.5, you can also generate a configuration with the Configuration Calculator.

SuperServer

Choose SuperServer if you have 1-2 databases with light load (1-3 simultaneously active users, up to about 20 users in total) and limited hardware resources.

SuperClassic Recommended for Firebird 2.5

Choose SuperClassic for stable applications (no “Abnormal termination” messages in firebird.log).

  • RAM 8-12 GB · up to 150 connections in total · 64-bit only firebird.conf
  • RAM 16-32 GB · up to 300 connections in total · 64-bit only firebird.conf

Classic

Choose Classic if your applications have stability problems, or if you use 32-bit UDFs.

  • RAM 8-12 GB · up to 150 connections in total 32-bit · 64-bit
  • RAM 16-32 GB · up to 300 connections in total 32-bit · 64-bit

How to proceed

  1. Download the configuration files for your Firebird version.
  2. Copy them into the Firebird folder, rename to firebird.conf (and databases.conf when provided), then restart Firebird. Disconnect all active users before the restart.
  3. If you intend to change architecture (for example SuperServer → SuperClassic), read the Firebird documentation for that change first.
Page buffers check

For all architectures, make sure you do not override the page buffers value in the database header page.

Run gstat -h databasename and confirm that Page buffers is 0. If it is set to another value, reset it with:

gfix -buff 0

Important

  • Always rename and keep a copy of your original firebird.conf and, for Firebird 3.0, databases.conf.
  • For Firebird 3.0, always review databases.conf. It should contain only values you explicitly set - and you should understand why you set them.
  • Settings from firebird.conf apply as defaults to all active databases on the server; databases.conf (Firebird 3.0+) can override them.
  • Do not forget general OS tuning - see the short performance checklist.

If you need a configuration tailored to your environment for the best possible performance, or if issues remain after applying a file from this collection, contact us for tailored optimization support.

Outdated / discontinued versions: Firebird 1.5, 2.0, 2.1

The files below are for outdated Firebird versions only. We still provide them for reference, but we strongly recommend migrating to a modern Firebird release and using the Configuration Calculator for Firebird 5, 4, 3, or 2.5.

Firebird version Description Download
Firebird 1.5 SuperServer 32-bit firebird_15_superserver.conf
Classic 32-bit firebird_15_classic.conf
Firebird 2.0 SuperServer 32-bit firebird_20_superserver.conf
Classic 32-bit firebird_20_classic.conf
Firebird 2.1 SuperServer 32-bit firebird_21_superserver_32bit.conf
SuperServer 64-bit firebird_21_superserver_64bit.conf
Classic 32-bit firebird_21_classic_32bit.conf
Classic 64-bit firebird_21_classic_64bit.conf