We are having to migrate a web server hosting a subversion repository via mod_dav_svn to a new machine and host name. To ease transition, we are looking at running the two web servers in parallel with repository NFS mounted on both at the same time. We can then progressively do a 'svn switch' on checked out working copies to new host name.
The concern is that each mod_dav_svn is a different version. The older is 1.3 and the newer is 1.6. Further, the actual repository (db/format) is '1', so potentially wasn't ever upgraded when we went to 1.3.
The release notes for 1.5 and 1.6 both say words to the effect:
Repository Upgrades - The Subversion 1.6 server works with 1.5 and older repositories, and it will not upgrade such repositories to 1.6 unless specifically requested to via the svnadmin upgrade command. This means that some of the new 1.6 features will not become available simply by upgrading your server: you will also have to upgrade your repositories. (We decided not to auto-upgrade repositories because we didn't want 1.6 to silently make repositories unusable by 1.5 — that step should be a conscious decision on the part of the repository admin.)
Also, since the repository format is still '1' even though using 1.3, then likely that the same applied to 1.3 as well.
So it doesn't look like there is any risk of 1.6 upgrading the repository and making it unusable to 1.3 at the same time. This will allow us to do our migrations and when we are done and old server shutdown, then we can do the 'svnadmin upgrade' on the repository to get it up to 1.6 and get access to any new features provided clients also 1.6.
Can anyone see any issues with this plan?