How to freeing space from svn repository

With the passage of time, considerably increases the disk space used by svn repository. While the cost of storage has dropped incredibly in the past few years, disk usage is still a valid concern for administrators seeking to version large amounts of data so the maintenance activities about to free disk space becomes necessary. Some of them are:

• Removing dead transactions;
• Purging unused Berkeley DB logfiles;
• Packing FSFS filesystems;
• Purging the svn history.

Removing dead transactions

Though they are uncommon, there are circumstances in which a Subversion commit process might fail, leaving behind in the repository the remnants of the revision-to-be that wasn't an uncommitted transaction and all the file and directory changes associated with it.
You can use the svnadmin lstxns command to list the names of the currently outstanding transactions and remove them with "svnadmin rmtxns" command.

Example: 

$ svnadmin lstxns myrepos
27
4c3
w33
$ svnadmin rmtxns myrepos `svnadmin lstxns myrepos`

Purging unused Berkeley DB logfiles

Removing unused Berkeley DB logfiles allows you to free disk space. Use the svnadmin list-unused-dblogs command to list the unused logfiles and remove them.
Example:

$ svnadmin list-unused-dblogs /var/svn/repos
/var/svn/repos/log.0000000127
/var/svn/repos/log.0000000128
/var/svn/repos/log.0000000129
$ rm `svnadmin list-unused-dblogs /var/svn/repos`

Prune the history

Also you can prune your history. For example: say you have 180 revisions, you can keep the latest history, say 30 revisions. This may also reduce the size of your subversion repository.

$ svnadmin dump /path/to/current/repo -r150:180 > newsvn.dump
# you can delete the old repo and then
$ svnadmin create /path/to/new/repo
$ svnadmin load /path/to/new/repo < newsvn.dump

Packing FSFS filesystems

FSFS-backed Subversion repositories create, by default, a new on-disk file for each revision added to the repository. Having thousands of these files present on your Subversion server, even when housed in separate shared directories, can lead to inefficiencies. To solve this problem, you can use "svnadmin pack" command. By concatenating all the files of a completed shard into a single “pack” file and  then removing the original per-revision files, svnadmin pack reduces the file count within a given shard down to just a single file. In doing so, it aids filesystem caches and reduces (to one) the number of times a file storage overhead penalty is paid.

Example:

$ svnadmin pack /var/svn/repos
Packing shard 0...done.
Packing shard 1...done.
…
Packing shard 100...done. 

A relevant consideration is that the svnadmin pack command has no effect on BDB-backed Subversion repositories.