Go to main content

man pages section 8: System Administration Commands

Exit Print View

Updated: Thursday, June 13, 2019
 
 

vfs_readahead (8)

Name

vfs_readahead - load the kernel buffer cache

Synopsis

vfs objects = readahead

Description

System Administration tools                                   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 part of version 4.9.3 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.



ATTRIBUTES
       See attributes(7) for descriptions of the following attributes:


       +---------------+-----------------------+
       |ATTRIBUTE TYPE |   ATTRIBUTE VALUE     |
       +---------------+-----------------------+
       |Availability   | service/network/samba |
       +---------------+-----------------------+
       |Stability      | Volatile              |
       +---------------+-----------------------+
NOTES
       This software was built from source available at
       https://github.com/oracle/solaris-userland.  The original community
       source was downloaded from
       https://download.samba.org/pub/samba/stable/samba-4.9.3.tar.gz

       Further information about this software can be found on the open source
       community website at http://www.samba.org/.



Samba 4.9.3                       01/24/2019                  VFS_READAHEAD(8)