Does "svnadmin dump" lock the repository?

Question

... what happens if someone tries to commit during a svnadmin dump REPOS_PATH?

The subversion book doesn't say anything about that.

Answer 1

A concurrently running svnadmin dump will not interfere with new commits. The resulting dump file, however, will only contain the revisions that were present in the repository when you started svnadmin dump.

You'll need to grab commits made while the initial dump was running with a second dump.

Other options you might be interested in:

svnadmin hotcopy
Unlike a dump file, this will include conf and hooks.

svnsync
For maintaining a read-only clone of an existing repository.

Of the three, I make the most use of svnsync. It allows me to keep a second copy of our repositories on a separate machine, which is closer to me. This makes for a nice backup, as well as for faster checkouts. (If the svnsync clone and the original have the same UUID, you can svn co svn://the-clone and then svn switch --relocate svn://the-clone https://the-original)