svn update and commit stopped working

Question

I've had subversion up and running with apache2 on an Ubuntu server for about a year now. I've used it almost every day without any problems until 4 days ago. I can browse my repositories through a web browser and I can also list my repositories using

svn list http://xx.xxx.xxx.xxx/svn/repository

But when I try to update or commit something the server hangs and I have to wait for about one minute until I can reach it again. I've searched everywhere but can't seem to find any solution. The apache error.log says

[Sun Mar 17 16:36:36 2013] [notice] caught SIGTERM, shutting down
PHP Warning:  Module 'ssh2' already loaded in Unknown on line 0
[Sun Mar 17 16:36:37 2013] [notice] Apache/2.2.22 (Ubuntu) DAV/2 SVN/1.6.17 PHP/5.3.10-1ubuntu3.6 with Suhosin-Patch configured -- resuming normal operations

and the other_vhosts_access.log says

- [17/Mar/2013:16:37:44 +0100] "OPTIONS /svn/repository HTTP/1.1" 401 677 "-" "SVN/1.6.18 (r1303927) neon/0.29.0"
- [17/Mar/2013:16:37:44 +0100] "OPTIONS /svn/repository HTTP/1.1" 401 677 "-" "SVN/1.6.18 (r1303927) neon/0.29.0"
user [17/Mar/2013:16:37:44 +0100] "OPTIONS /svn/repository HTTP/1.1" 200 876 "-" "SVN/1.6.18 (r1303927) neon/0.29.0"
user [17/Mar/2013:16:37:44 +0100] "OPTIONS /svn/repository HTTP/1.1" 200 876 "-" "SVN/1.6.18 (r1303927) neon/0.29.0"
user [17/Mar/2013:16:37:44 +0100] "PROPFIND /svn/repository HTTP/1.1" 207 554 "-" "SVN/1.6.18 (r1303927) neon/0.29.0"
user [17/Mar/2013:16:37:44 +0100] "PROPFIND /svn/repository HTTP/1.1" 207 554 "-" "SVN/1.6.18 (r1303927) neon/0.29.0"
user [17/Mar/2013:16:37:44 +0100] "PROPFIND /svn/repository HTTP/1.1" 207 554 "-" "SVN/1.6.18 (r1303927) neon/0.29.0"
user [17/Mar/2013:16:37:44 +0100] "PROPFIND /svn/repository HTTP/1.1" 207 554 "-" "SVN/1.6.18 (r1303927) neon/0.29.0"
user [17/Mar/2013:16:37:44 +0100] "PROPFIND /svn/repository/!svn/vcc/default HTTP/1.1" 207 453 "-" "SVN/1.6.18 (r1303927) neon/0.29.0"
user [17/Mar/2013:16:37:44 +0100] "PROPFIND /svn/repository/!svn/vcc/default HTTP/1.1" 207 453 "-" "SVN/1.6.18 (r1303927) neon/0.29.0"
user [17/Mar/2013:16:37:44 +0100] "PROPFIND /svn/repository/!svn/bln/20 HTTP/1.1" 207 468 "-" "SVN/1.6.18 (r1303927) neon/0.29.0"
user [17/Mar/2013:16:37:44 +0100] "PROPFIND /svn/repository/!svn/bln/20 HTTP/1.1" 207 468 "-" "SVN/1.6.18 (r1303927) neon/0.29.0"
user [17/Mar/2013:16:37:44 +0100] "PROPFIND /svn/repository HTTP/1.1" 207 554 "-" "SVN/1.6.18 (r1303927) neon/0.29.0"
user [17/Mar/2013:16:37:44 +0100] "PROPFIND /svn/repository HTTP/1.1" 207 554 "-" "SVN/1.6.18 (r1303927) neon/0.29.0"
user [17/Mar/2013:16:37:45 +0100] "PROPFIND /svn/repository/!svn/vcc/default HTTP/1.1" 207 453 "-" "SVN/1.6.18 (r1303927) neon/0.29.0"
user [17/Mar/2013:16:37:45 +0100] "PROPFIND /svn/repository/!svn/vcc/default HTTP/1.1" 207 453 "-" "SVN/1.6.18 (r1303927) neon/0.29.0"
user [17/Mar/2013:16:37:45 +0100] "PROPFIND /svn/repository/!svn/bln/20 HTTP/1.1" 207 468 "-" "SVN/1.6.18 (r1303927) neon/0.29.0"
user [17/Mar/2013:16:37:45 +0100] "PROPFIND /svn/repository/!svn/bln/20 HTTP/1.1" 207 468 "-" "SVN/1.6.18 (r1303927) neon/0.29.0"

I've tried to reinstall subversion, restart the computer, verify and recover my repositories but nothing helped. Does anyone know what the problem can be?

Update: After looking into Module 'ssh2' already loaded in Unknown on line 0, the error log says the following:

[Wed Mar 20 22:27:45 2013] [notice] caught SIGTERM, shutting down [Wed Mar 20 22:27:46 2013] [notice] Apache/2.2.22 (Ubuntu) DAV/2 SVN/1.7.8 PHP/5.3.10-1ubuntu3.6 with Suhosin-Patch configured -- resuming normal operations 

Answer 1

Not the answer you're looking for but here goes:

Switch to Git.

You won't regret it! :-)

Answer 2

I had a similar problem once that was caused by a bug in a pre-commit hook.

Create a new test repository (without any hooks) and see if you can commit there.

You should also check the integrity of your repositories. svnadmin verify will not catch all errors - try svnadmin dump REPOS > /dev/nul.