One SVN repository or many?

Question

If you have multiple, unrelated projects, is it a good idea to put them in the same repository?

myRepo/projectA/trunk myRepo/projectA/tags myRepo/projectA/branches myRepo/projectB/trunk myRepo/projectB/tags myRepo/projectB/branches 

or would you create new repositories for each?

myRepoA/trunk myRepoA/tags myRepoA/branches myRepoB/trunk myRepoB/tags myRepoB/branches 

What are the pros and cons of each? All that I can currently think of is that you get mixed revision numbers (so what?), and that you can't use svn:externals unless the repository is actually external. (i think?)

The reason I ask is because I'm considering consolidating my multiple repos into one, since my SVN host has started charging per repo.

Answer 1

The single vs. multiple issue comes down to personal or organizational preference.

Management of multiple vs. single mainly comes down to access control and maintenance.

Access control for a single repository can be contained in a single file; Multiple repositories are may require multiple files. Maintenance has similar issues - one big backup, or a lot of little backups.

I manage my own. There's one repository, multiple projects, each with its own tags, trunk and branches. If one gets too big or I need to physically isolate a customer's code for their comfort, I can quickly and easily create a new repository.

I recently consulted with a relatively large firm on migrating multiple source code control systems to Subversion. They have ~50 projects, ranging from very small to enterprise applications and their corporate website. Their plan? Start with a single repository, migrate to multiple if necessary. The migration is almost complete and they're still on a single repository, no complaints or issues reported due to it being a single repository.

This isn't a binary, black & white issue.

Do what works for you - were I in your position, I'd combine projects into a single repository as fast as I could type the commands, because the cost would be a major consideration in my (very, very small) company.

JFTR:

revision numbers in Subversion really have no meaning outside the repository. If you need meaningful names for a revision, create a TAG

Commit messages are easily filtered by path in the repository, so reading only those related to a particular project is a trivial exercise.

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Edit: See Blade's response for details on using a single authorization/authentication configuration for SVN.