<samba:parameter name="level2 oplocks" context="S" type="boolean" xmlns:samba="http://www.samba.org/samba/DTD/samba-doc"> <description> <para>This parameter controls whether Samba supports level2 (read-only) oplocks on a share.</para> <para>Level2, or read-only oplocks allow Windows NT clients that have an oplock on a file to downgrade from a read-write oplock to a read-only oplock once a second client opens the file (instead of releasing all oplocks on a second open, as in traditional, exclusive oplocks). This allows all openers of the file that support level2 oplocks to cache the file for read-ahead only (ie. they may not cache writes or lock requests) and increases performance for many accesses of files that are not commonly written (such as application .EXE files).</para> <para>Once one of the clients which have a read-only oplock writes to the file all clients are notified (no reply is needed or waited for) and told to break their oplocks to "none" and delete any read-ahead caches.</para> <para>It is recommended that this parameter be turned on to speed access to shared executables.</para> <para>For more discussions on level2 oplocks see the CIFS spec.</para> <para> Currently, if <smbconfoption name="kernel oplocks"/> are supported then level2 oplocks are not granted (even if this parameter is set to <constant>yes</constant>). Note also, the <smbconfoption name="oplocks"/> parameter must be set to <constant>yes</constant> on this share in order for this parameter to have any effect.</para> </description> <related>oplocks</related> <related>kernel oplocks</related> <value type="default">yes</value> </samba:parameter>