IssueDb4UnderXenDomU

Symptoms

Summary: program fails with error: "unable to initialize mutex: Function not implemented"

A program (rpm, OpenLDAP's slapd) aborts with error:

    rpmdb: unable to initialize mutex: Function not implemented
    ...
    error: db4 error(38) from dbenv->open: Function not implemented

The exact db4 function in which the problem occurs may vary, but the error code 38 and the message unable to initialize mutex: Function not implemented are constant.

The problem we are facing (and its variations, depending on the workarounds that one can try) is quite accurately described at http://www.openldap.org/lists/openldap-software/200603/msg00199.html

Occurrences

Reproduceable on any Xen DomU running RHEL4-derived systems (CentOS4, SL4, SLC4).

Observations

On the site-BDII, the problem was fixed by using the "ldbm" backend and avoiding Berkeley DB4 completely.

We cannot do this for Phedex, since it uses a CMS-built version of apt+rpm+db4, so we cannot rebuild that with different flags.

Solution or Workaround

None known so far.

I wasn't able to find much information by googling: all the related pages date back to 2005/2006 (when CentOS4/RHEL4 was current), and the links to software packages or patches are often broken. Some suggest fixing the problem by recompiling the libc with a special gcc option; finally I found the exact patch here:

http://lists.centos.org/pipermail/centos-devel/2005-December/000175.html

Monitoring for this condition

-- RiccardoMurri - 05 Nov 2008