Using the lmdb database backend
LMDB back end
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.
Calculating space used
As discussed in the article lmdb memory utilisation and file sizes, the size of the database on disk does not reflect the actual space used. To calculate space used.
Run: mdb_stat -ne file