VFS_PREOPEN(1M) System Administration tools VFS_PREOPEN(1M)NAMEvfs_preopen - Hide read latencies for applications reading numbered
files
SYNOPSIS
vfs objects = preopen
DESCRIPTION
This VFS module is part of the samba(7) suite.
This module assists applications that want to read numbered files in
sequence with very strict latency requirements. One area where this
happens in video streaming applications that want to read one file per
frame.
When you use this module, a number of helper processes is started that
speculatively open files and read a number of bytes to prime the file
system cache, so that later on when the real application's request
comes along, no disk access is necessary.
This module is stackable.
OPTIONS
preopen:names = /pattern/
preopen:names specifies the file name pattern which should trigger
the preopen helpers to do their work. We assume that the files are
numbered incrementally. So if your file names are numbered
FRAME00000.frm FRAME00001.frm and so on you would list them as
preopen:names=/FRAME*.frm/
preopen:num_bytes = BYTES
Specifies the number of bytes the helpers should speculatively
read, defaults to 1.
preopen:helpers = NUM-PROCS
Number of forked helper processes, defaults to 1.
preopen:queuelen = NUM-FILES
Number of files that should be speculatively opened. Defaults to
the 10 subsequent files.
VERSION
This man page is correct for version 3.3 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.
The PREOPEN VFS module was created with contributions from Volker
Lendecke and the developers at IBM.
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_PREOPEN(1M)
