This bug has been copied from bug #480048 and has been proposed to be backported to 5.3 z-stream (EUS).
backported
Release note added. If any revisions are required, please set the "requires_release_notes" flag to "?" and edit the "Release Notes" field accordingly. All revisions will be proofread by the Engineering Content Services team. New Contents: * multipath must be able to open a file descriptor for each path that it monitors, plus 32 other file descriptors. By default, multipath can open 1024 file descriptors, which is sufficient for it to monitor 992 paths. If multipath is not able to open all the file descriptors that it needs, the multipath daemon will not function correctly, and in Red Hat Enterprise Linux 5.3, this situation exposes a kernel memory leak that can cause a system to stop responding. Previously, multipath would not warn users that it could not open enough file descriptors. Now, when multipath runs out of file descriptors, it prints an error message. System administrators can allow multipath to open more file descriptors by setting "max_fds" in the multipath.conf file to a sufficiently high number, or by setting "max_fds" to "max" to allow multipath to open as many file descriptors as the system allows.
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on therefore solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHBA-2009-0283.html