Re: DOC: Wal update

[Bruce Momjian <bruce(at)momjian(dot)us>]

Zdenek Kotala wrote:
> I add few sentences how to write cache works on Solaris platform.

I have updated our documentation with the attached patch.  I was able to
verify all the information in this change.  

I changed your original wording because the statement that UFS turns off
write cache seemed unclear because the file system seems independent of
the disk write cache.  (What happens if you have UFS and ZFS on the same
drive?)

Anyway I think the attached wording is fine.

-- 
  Bruce Momjian  <bruce(at)momjian(dot)us>        http://momjian.us
  EnterpriseDB                             http://postgres.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +

Index: doc/src/sgml/wal.sgml
===================================================================
RCS file: /cvsroot/pgsql/doc/src/sgml/wal.sgml,v
retrieving revision 1.51
diff -c -c -r1.51 wal.sgml
*** doc/src/sgml/wal.sgml	16 Dec 2007 14:05:12 -0000	1.51
--- doc/src/sgml/wal.sgml	29 Dec 2007 17:53:58 -0000
***************
*** 65,74 ****
     write caching.  On <productname>FreeBSD</> use
     <application>atacontrol</>.  (For SCSI disks use <ulink
     url="http://sg.torque.net/sg/sdparm.html";><application>sdparm</></ulink>
!    to turn off <literal>WCE</>.)  On <productname>Windows</> if
!    <varname>wal_sync_method</> is <literal>open_datasync</> (the default),
!    write caching is disabled by unchecking <literal>My
!    Computer\Open\{select disk
     drive}\Properties\Hardware\Properties\Policies\Enable write caching on
     the disk</>.  Also on Windows, <literal>fsync</> and
     <literal>fsync_writethrough</> never do write caching.
--- 65,78 ----
     write caching.  On <productname>FreeBSD</> use
     <application>atacontrol</>.  (For SCSI disks use <ulink
     url="http://sg.torque.net/sg/sdparm.html";><application>sdparm</></ulink>
!    to turn off <literal>WCE</>.)  On <productname>Solaris</> the disk
!    write cache is controlled by <ulink
!    url="http://www.sun.com/bigadmin/content/submitted/format_utility.jsp";><literal>format
!    -e</></ulink>. (The Solaris <acronym>ZFS</> file system is safe with
!    disk write-cache enabled because it issues its own disk cache flush
!    commands.)  On <productname>Windows</> if <varname>wal_sync_method</>
!    is <literal>open_datasync</> (the default), write caching is disabled
!    by unchecking <literal>My Computer\Open\{select disk
     drive}\Properties\Hardware\Properties\Policies\Enable write caching on
     the disk</>.  Also on Windows, <literal>fsync</> and
     <literal>fsync_writethrough</> never do write caching.