After running Jenkins for a few days there are a large number of SSH processes running on the server:
root 19732 0.0 0.6 11632 3092 ? Ss May02 0:00 _ sshd: secsvn [priv]
secsvn 19736 0.0 0.6 11632 3332 ? S May02 0:00 | _ sshd: secsvn@notty
secsvn 19737 0.0 0.3 6152 2052 ? Ss May02 0:00 | _ svnserve -t --tunnel-user=sjm217 -r ...
root 19756 0.0 0.6 11632 3092 ? Ss May02 0:00 _ sshd: secsvn [priv]
secsvn 19760 0.0 0.6 11632 3332 ? S May02 0:00 | _ sshd: secsvn@notty
secsvn 19761 0.0 0.3 6148 1944 ? Ss May02 0:00 | _ svnserve -t --tunnel-user=sjm217 -r ...
root 19780 0.0 0.5 11632 2676 ? Ss May02 0:00 _ sshd: secsvn [priv]
secsvn 19784 0.0 0.5 11632 2944 ? S May02 0:00 | _ sshd: secsvn@notty
secsvn 19785 0.0 0.3 6152 1928 ? Ss May02 0:00 | _ svnserve -t --tunnel-user=sjm217 -r ...
...

Perhaps related is the following error in the log
04-May-2011 15:03:08 hudson.model.Run run
INFO: cheri #10 main build action completed: SUCCESS

04-May-2011 15:03:08 hudson.scm.SubversionSCM$CheckOutTask checkClockOutOfSync
INFO: Failed to estimate the remote time stamp
org.tmatesoft.svn.core.SVNException: svn: 'stat' not implemented
svn: Unknown command 'stat'
at org.tmatesoft.svn.core.internal.wc.SVNErrorManager.error(SVNErrorManager.java:126)
at org.tmatesoft.svn.core.internal.wc.SVNErrorManager.error(SVNErrorManager.java:110)
at org.tmatesoft.svn.core.internal.io.svn.SVNRepositoryImpl.handleUnsupportedCommand(SVNRepositoryImpl.java:1368)
at org.tmatesoft.svn.core.internal.io.svn.SVNRepositoryImpl.info(SVNRepositoryImpl.java:1212)
at hudson.scm.SubversionSCM$CheckOutTask.checkClockOutOfSync(SubversionSCM.java:732)
at hudson.scm.SubversionSCM$CheckOutTask.invoke(SubversionSCM.java:709)
at hudson.scm.SubversionSCM$CheckOutTask.invoke(SubversionSCM.java:691)
at hudson.FilePath.act(FilePath.java:756)
at hudson.FilePath.act(FilePath.java:738)
at hudson.scm.SubversionSCM.checkout(SubversionSCM.java:684)
at hudson.scm.SubversionSCM.checkout(SubversionSCM.java:633)
at hudson.model.AbstractProject.checkout(AbstractProject.java:1181)
at hudson.model.AbstractBuild$AbstractRunner.checkout(AbstractBuild.java:536)
at hudson.model.AbstractBuild$AbstractRunner.run(AbstractBuild.java:424)
at hudson.model.Run.run(Run.java:1374)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:46)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:145)
Caused by: org.tmatesoft.svn.core.SVNException: svn: Unknown command 'stat'
at org.tmatesoft.svn.core.internal.wc.SVNErrorManager.error(SVNErrorManager.java:64)
at org.tmatesoft.svn.core.internal.wc.SVNErrorManager.error(SVNErrorManager.java:51)
at org.tmatesoft.svn.core.internal.io.svn.SVNReader.handleFailureStatus(SVNReader.java:269)
at org.tmatesoft.svn.core.internal.io.svn.SVNReader.parse(SVNReader.java:248)
at org.tmatesoft.svn.core.internal.io.svn.SVNConnection.read(SVNConnection.java:260)
at org.tmatesoft.svn.core.internal.io.svn.SVNConnection.authenticate(SVNConnection.java:160)
at org.tmatesoft.svn.core.internal.io.svn.SVNRepositoryImpl.authenticate(SVNRepositoryImpl.java:1265)
at org.tmatesoft.svn.core.internal.io.svn.SVNRepositoryImpl.info(SVNRepositoryImpl.java:1191)
... 14 more
Caused by: org.tmatesoft.svn.core.SVNErrorMessage: svn: Unknown command 'stat'
at org.tmatesoft.svn.core.SVNErrorMessage.create(SVNErrorMessage.java:200)
at org.tmatesoft.svn.core.SVNErrorMessage.create(SVNErrorMessage.java:146)
at org.tmatesoft.svn.core.SVNErrorMessage.create(SVNErrorMessage.java:89)
at org.tmatesoft.svn.core.internal.io.svn.SVNReader.getErrorMessage(SVNReader.java:283)
at org.tmatesoft.svn.core.internal.io.svn.SVNReader.handleFailureStatus(SVNReader.java:261)
... 19 more