I'm running Hudson 1.225 and I run into this error after a couple of builds.

started
[workspace] $ cleartool rmview -force hudson_base_1_2_Nightly
FATAL: java.io.IOException: Too many open files

java.io.IOException: java.io.IOException: Too many open files
at java.lang.UNIXProcess.<init>(UNIXProcess.java:148)
at java.lang.ProcessImpl.start(ProcessImpl.java:65)
at java.lang.ProcessBuilder.start(ProcessBuilder.java:451)

at hudson.Proc$LocalProc.<init>(Proc.java:104)
at hudson.Proc$LocalProc.<init>(Proc.java:82)
at hudson.Launcher$LocalLauncher.createLocalProc(Launcher.java:291)
at hudson.Launcher$LocalLauncher.launch(Launcher.java:282)

at
hudson.plugins.clearcase.HudsonClearToolLauncher.run(HudsonClearToolLauncher.java:54)
at hudson.plugins.clearcase.ClearToolSnapshot.rmview(ClearToolSnapshot.java:64)
at
hudson.plugins.clearcase.action.UcmSnapshotCheckoutAction.checkout(UcmSnapshotCheckoutAction.java:33)

at
hudson.plugins.clearcase.AbstractClearCaseScm.checkout(AbstractClearCaseScm.java:133)
at
hudson.plugins.clearcase.AbstractClearCaseScm.checkout(AbstractClearCaseScm.java:113)
at hudson.model.AbstractProject.checkout(AbstractProject.java:574)

at hudson.model.AbstractBuild$AbstractRunner.checkout(AbstractBuild.java:251)
at hudson.model.AbstractBuild$AbstractRunner.run(AbstractBuild.java:225)
at hudson.model.Run.run(Run.java:771)
at hudson.maven.MavenModuleSetBuild.run(MavenModuleSetBuild.java:202)

at hudson.model.ResourceController.execute(ResourceController.java:70)
at hudson.model.Executor.run(Executor.java:82)

Not sure if it is a plugin (ClearCase) or Hudson core issue. This occurs both
with 0.5 and 0.6 of the ClearCase plugin.