10.4. Upgrading Subversion Eventually, you are going to want to upgrade your Subversion installation. Presumably, you would like to do this without damaging your existing repository and its precious data. Fortunately, the Subversion developers thought about this, and have made upgrading Subversion a relatively easy task. The exact effort that needs to be put into an upgrade depends on the version you are upgrading to. If you are upgrading to a patch release (e.g., from 1.1.0 to 1.1.1), you don't have to take any special action, other than upgrading the Subversion executables per the software upgrade process for your particular system. Additionally, you can rest assured that you will be able to undo the upgrade if the new version fails to work correctly for you. Subversion policy states that all patch releases will be forward and backward compatible, so if you perform the upgrade and have problems with the new version, you can always go back to the previous version. If you are upgrading a minor release (e.g., from 1.0 to 1.1), the upgrade process is identical to patch releases. Just upgrade the executables and go. Although minor releases will always be forward compatible, they won't necessarily be backward compatible. After you have performed an upgrade, you may not be able to take your repository back to an older version. If you are upgrading to a new major version release (e.g., from 1.0 to 2.0), it is possible that the database format has changed, and your current database won't work after the upgrade. This means that you need to create a dump of the database before the upgrade, upgrade Subversion, then use svnadmin load to reload the data into a new repository, just as if you were recovering after a crash (see Section 10.2.4, "Recovering"). It's very important, though, to perform the dump before you upgrade Subversion, as the new version may not be able to dump the old repository.
I cannot stress enough, however, the importance of backing up your repository before even thinking about a Subversion upgrade, even if you are not going across a major version release. You never know what will happen during an upgrade, and a simple mistake could potentially destroy your repository. |
