Title: mail-mta/postfix-3.11.0: Default database change
Author: Eray Aslan <[email protected]>
Posted: 2026-03-15
Revision: 1
News-Item-Format: 2.0
Display-If-Installed: mail-mta/postfix
The default local database type in mail-mta/postfix has been hash for local
files and btree for caches and both file types depend on sys-libs/db. However,
BerkeleyDB has not been developed sufficiently in recent years and the
licensing change in 2013 made using the latest versions of BerkeleyDB
problematic. Consequently, we are stuck with using ancient versions of
BerkeleyDB and there is a general tendency in the Linux ecosystem to sunset
BerkeleyDB support.
Postfix made switching database types easier with its latest release. We will
be changing the default database type in postfix for both local databases and
caches to lmdb starting with mail-mta/postfix-3.11.0.
# Timeline:
- mail-mta/postfix-3.11.0: March 2026. Both lmdb and berkdb USE flags are on
by default. BerkeleyDB is still supported but the default database and cache
type changes to lmdb.
- mail-mta/postfix-3.12.0: Expected Q1 2027. BerkeleyDB support will be off by
default. You will need to turn it on manually if still needed.
mail-mta/postfix will continue supporting BerkeleyDB until it is sunsetted
in Gentoo.
Changing the default database and cache types in postfix-3.11.0 requires
migration for the entries in main.cf and master.cf that do not specify a
database type.
It is almost always a good idea to specify database type in main.cf and
master.cf and in your postmap commands. As you are always specifying the
database type, the default database and cache type settings do not come into
play.
Option 1: Accept the new defaults and migrate to lmdb. The default USE flags
take effect and lmdb becomes the new default when
>=mail-mta/postfix-3.11.0 is installed. All local database files without
a specified type and, optionally, caches need to be migrated to lmdb.
If your configuration is simple or if you are familiar with Postfix
configuration, a few "grep" commands will find all the problems, and a few
edits will be easy to make.
Read https://www.postfix.org/NON_BERKELEYDB_README.html#manual for a complete
walk through and the commands you can run to find instances of BerkeleyDB usage
in your postfix configuration.
Option 2: If your configuration is too complex for the manual migration step
above or if you are not familiar with the details of your postfix
configuration, postfix provides enable-redirect[1] and enable-reindex[2]
options. Read the documentation for the details and their caveats. They provide
valuable help in migration, especially for an operating system that do not have
BerkeleyDB support anymore - which is NOT the case for Gentoo. However, these
options still help in complex configuration cases.
Option 3: Turning off lmdb USE flag is not recommended but is possible. The
default stays the same as previous versions of postfix, namely hash for local
files and btree for caches. No further action is necessary until BerkeleyDB
support is sunsetted in Gentoo when you will have to do the above migration.
For more details, please read:
https://www.postfix.org/NON_BERKELEYDB_README.html
[1] https://www.postfix.org/NON_BERKELEYDB_README.html#enable-redirect
[2] https://www.postfix.org/NON_BERKELEYDB_README.html#enable-reindex
