Comment 4 for bug 120792

This documentation:
      http://www.redhat.com/docs/manuals/enterprise/RHEL-5-manual/Cluster_Logical_Volume_Manager/LV_create.html
explains that you can keep the log in memory only, which requires a re-scan of the mirror on bootup.

However, it still doesn't work:

       % sudo lvcreate -L 1G --corelog -m1 -n testmirror Ubuntu
        LV testmirror_mlog: segment 1 has inconsistent PV area 0
        Internal error: LV segments corrupted in testmirror_mlog.
        Failed to create mirror log.

..which is anyway reported in #121024, which is tagged as duplicate of #121527, which I'll tag as duplicate of this.