Difference between the format and db/format files in a Subversion repository

Question

What is the difference between the following two files on an SVN server (ie not in a checked out repository)?

format
db/format

In our repositories the contents of the first is 5 while the contents of the second is 2

Answer 1

The format file contains information about Subversion repository format, while db/format holds information about Subversion Repository File System (FS) format.

Repository format number:

• Formats 0, 1 and 2 were pre-1.0.
• Format 3 was current for 1.0 through to 1.3.
• Format 4 was an abortive experiment during the development of the locking feature in the lead up to 1.2.
• Format 5 was new in 1.4, and is the first format which may contain BDB or FSFS filesystems with a FS format other than 1, since prior formats are accepted by some versions of Subversion which do not pay attention to the FS format number.

FSFS format number:

• Format 1, understood by Subversion 1.1+
• Format 2, understood by Subversion 1.4+, introduced support for svn diff version 1
• Format 3, understood by Subversion 1.5+, sharded layout and storing merge tracking information
• Format 4, understood by Subversion 1.6+, represention sharing and repository packing
• Format 5, understood by Subversion 1.7+, revision properties packing