File system replication and DRBD

The attached patch mentions file system replication as a high
availability solution in the shared hardware section, and mentions DRBD
as a popular solution.  Backpatched to 8.2.X.

--
  Bruce Momjian   bruce@momjian.us
  EnterpriseDB    http://www.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +
Index: doc/src/sgml/high-availability.sgml
===================================================================
RCS file: /cvsroot/pgsql/doc/src/sgml/high-availability.sgml,v
retrieving revision 1.15
diff -c -c -r1.15 high-availability.sgml
*** doc/src/sgml/high-availability.sgml    1 Dec 2006 03:19:48 -0000    1.15
--- doc/src/sgml/high-availability.sgml    1 Feb 2007 21:00:35 -0000
***************
*** 99,108 ****
      disk array fails or becomes corrupt, the primary and standby
      servers are both nonfunctional.  Another issue is that the
      standby server should never access the shared storage while
!     the primary server is running.  It is also possible to use
!     some type of file system mirroring to keep the standby server
!     current, but the mirroring must be done in a way that ensures the
!     standby server has a consistent copy of the file system.
     </para>

  <!--
--- 99,115 ----
      disk array fails or becomes corrupt, the primary and standby
      servers are both nonfunctional.  Another issue is that the
      standby server should never access the shared storage while
!     the primary server is running.
!    </para>
!
!    <para>
!     A modified version of shared hardware functionality is file system
!     replication, where all changes to a file system are mirrored to a file
!     system residing on another computer.  The only restriction is that
!     the mirroring must be done in a way that ensures the standby server
!     has a consistent copy of the file system — specifically, writes
!     to the standby must be done in the same order as those on the master.
!     DRBD is a popular file system replication solution for Linux.
     </para>

  <!--