PostgreSQL’s number one priority is the integrity of your data. FAT and FAT32 file systems simply do not offer the reliability required to allow this. In addition, the lack of security features offered by FAT make it impossible to secure the raw data files from unauthorized modification. Finally, PostgreSQL utilizes a feature called ‘reparse points’ to implement table spaces. This feature is not available on FAT partitions.
The NTFS file system is a journal led file system offering much better reliability and crash recovery. In addition, it has a comprehensive access control system and offers the reparse point functionality used by PostgreSQL.
For this reason, the PostgreSQL installer package will not initialize a database cluster on anything but an NTFS partition. The server and utilities may be installed on any partition type.
It is recognized however, that on some systems such as developer’s PCs, FAT partitions may be the only choice. In such cases, you can simply install PostgreSQL as normal, but without initializing the database cluster. When the installation has finished, manually run the ‘initdb.exe’ program on the FAT partition. Security and reliability will be compromised however, and any attempts to create table spaces will fail.