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<chapter id="wal">

<title>Reliability and the Write-Ahead Log</title>

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

disabled by unchecking <literal>My Computer\Open\{select disk

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</>.

the disk</>. Also on Windows, <literal>fsync</> and

<literal>fsync_writethrough</> never use write caching.

</para>

<para>