Using the lmdb database backend
LMDB back end
Samba can use an LMDB back end instead of the default TDB back end. The LMDB back end permits database sizes greater than 4Gb.
The LMDB backend can be enabled when provisioning or joining a domain using the
--backend-store=mdb option. The maximum size of the database files defaults to 8Gb, this can be changed with the
|This is a hard limit and Samba will fail if this limit is exceeded. There is currently no way to resize a Samba LMBD database.|
High virtual memory allocation
LMDB uses memory mapped files so if using the default database size of 8Gb the virtual memory reported by htop for Samba processes is typically 40Gb or 80Gb. This is normal and is not normally a concern, see the following article on lmdb memory utilisation and file sizes.
Database file sizes
Identifying an LMDB file
All Samba LMDB data files have an associated lock file with the extension
.ldb-lock and the data file has a .ldb extension.