vfs_preopen

Name

vfs_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. +