[RHEL5] About workaround and similar issue of BZ#578977 and BZ#599737.

Issue

• Customer encountered following BZ issue.

  • https://bugzilla.redhat.com/show_bug.cgi?id=578977
    Bug 578977 - vm.drop_caches corrupts hugepages and causes Oracle Database ORA-600 crashes
  • https://bugzilla.redhat.com/show_bug.cgi?id=599737
    Bug 599737 - vm.drop_caches corrupts hugepages and causes Oracle Database ORA-600 crashes [rhel-5.5.z]

• We received following questions about these BZ from the customer. Could you please answer the questions?

  • Q1. Is there any workaround except for kernel update to resolve these BZ issue? For example, can we avoid this issue if 'sysctl -w vm.drop_caches=1' is not peformed?
  • Q2. If there are similar other issues in the environment with Oracle Database and hugepages, please let me know about details(problem and workaround). For example, I found following fix as a likely issue, but we can not access BZ#593131.
  • Excerpt from kernel changelog.

    2010-07-22 22:00:00
    Jarod Wilson <<a class="make_room_for_kcs" href="mailto:jarod@redhat.com">jarod@redhat.com</a>> [2.6.18-208.el5]:
    - [mm] properly release all hugepages on database shutdown (Larry Woodman) [593131]