VFS_READAHEAD(1M) System Administration tools VFS_READAHEAD(1M)NAMEvfs_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:
· K - BYTES is a number of kilobytes
· M - BYTES is a number of megabytes
· 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.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌────────────────────┬─────────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├────────────────────┼─────────────────────────────────┤
│Availability │ SUNWsmbar, SUNWsmbac, SUNWsmbau │
├────────────────────┼─────────────────────────────────┤
│Interface Stability │ External │
└────────────────────┴─────────────────────────────────┘
NOTES
Source code for Samba is available in the SUNWsmbaS package.
Samba(7) delivers the set of four SMF(5) services as can be seen from
the following example:
$ svcs samba wins winbind swat
STATE STIME FMRI
disabled Apr_21 svc:/network/samba:default
disabled Apr_21 svc:/network/winbind:default
disabled Apr_21 svc:/network/wins:default
disabled Apr_21 svc:/network/swat:default
where the services are:
"samba"
runs the smbd daemon managing the CIFS sessions
"wins"
runs the nmbd daemon enabling the browsing (WINS)
"winbind"
runs the winbindd daemon making the domain idmap
"swat"
Samba Web Administration Tool is a service providing access to
browser-based Samba administration interface and on-line
documentation. The service runs on software loopback network
interface on port 901/tcp, i.e. opening "http://localhost:901/" in
browser will access the SWAT service on local machine.
Please note: SWAT uses HTTP Basic Authentication scheme where user name
and passwords are sent over the network in clear text. In the SWAT case
the user name is root. Transferring such sensitive data is advisable
only on the software loopback network interface or over secure
networks.
Samba 3.6 04/10/2012 VFS_READAHEAD(1M)