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Document how to turn off disk write cache on popular operating systems.

This commit is contained in:
Bruce Momjian 2007-12-10 14:05:05 +00:00
parent 8828689ae9
commit 51a33519b0
1 changed files with 12 additions and 3 deletions
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15
doc/src/sgml/wal.sgml
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<!-- $PostgreSQL: pgsql/doc/src/sgml/wal.sgml,v 1.46 2007/11/28 15:42:31 petere Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/wal.sgml,v 1.47 2007/12/10 14:05:05 momjian Exp $ -->
<chapter id="wal">
<title>Reliability and the Write-Ahead Log</title>
@ -58,8 +58,17 @@
while some are write-back, and the
same concerns about data loss exist for write-back drive caches as
exist for disk controller caches. Consumer-grade IDE drives are
particularly likely to contain write-back caches that will not
survive a power failure.
particularly likely to have write-back caches that will not survive a
power failure. To check write caching on <productname>Linux</> use
<command>hdparm -I</>; it is enabled if there is a <literal>*</> next
to <literal>Write cache</>. <command>hdparm -W</> can to turn off
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</> write caching is
controlled by <literal>My Computer\Open\{select disk
drive}\Properties\Hardware\Properties\Policies\Enable write caching on
the disk</>.
</para>
<para>