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vfs_readahead(8)                                              vfs_readahead(8)




NAME

       vfs_readahead - pre-load the kernel buffer cache


SYNOPSIS

       vfs objects = readahead


DESCRIPTION

       This VFS module is part of the samba(7) suite.

       This  vfs_readahead  VFS module detects read requests at multiples of a
       given offset (hex 0x80000 by default) and then  tells  the  kernel  via
       either the readahead system call (on Linux) or the posix_fadvise system
       call to pre-fetch this data into the buffer cache.

       This module is useful for Windows Vista clients reading data using  the
       Windows  Explorer program, which asynchronously does multiple file read
       requests at offset boundaries of 0x80000 bytes.

       The offset multiple used is given by the readahead:offset option, which
       defaults to 0x80000.

       The  size  of  the  disk  read operations performed by vfs_readahead is
       determined by the readahead:length option. By default this  is  set  to
       the same value as the readahead:offset option and if not set explicitly
       will use the current value of readahead:offset.

       This module is stackable.


OPTIONS

       readahead:offset = BYTES
          The offset multiple that causes readahead to  be  requested  of  the
          kernel buffer cache.

       readahead:length = BYTES
          The  number  of  bytes  requested  to be read into the kernel buffer
          cache on each readahead call.

       The following suffixes may be applied to BYTES:

       o  K - BYTES is a number of kilobytes

       o  M - BYTES is a number of megabytes

       o  G - BYTES is a number of gigabytes


EXAMPLES

            [hypothetical]
            vfs objects = readahead



VERSION

       This man page is correct for version 3.0.25 of the Samba suite.


AUTHOR

       The original Samba software  and  related  utilities  were  created  by
       Andrew  Tridgell.  Samba  is now developed by the Samba Team as an Open
       Source project similar to the way the Linux kernel is developed.




                                                              vfs_readahead(8)

Mac OS X 10.6 - Generated Thu Sep 17 20:26:31 CDT 2009
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