1VFS_PREOPEN(8)            System Administration tools           VFS_PREOPEN(8)
2
3
4

NAME

6       vfs_preopen - Hide read latencies for applications reading numbered
7       files
8

SYNOPSIS

10       vfs objects = preopen
11

DESCRIPTION

13       This VFS module is part of the samba(7) suite.
14
15       This module assists applications that want to read numbered files in
16       sequence with very strict latency requirements. One area where this
17       happens in video streaming applications that want to read one file per
18       frame.
19
20       When you use this module, a number of helper processes is started that
21       speculatively open files and read a number of bytes to prime the file
22       system cache, so that later on when the real application's request
23       comes along, no disk access is necessary.
24
25       This module is stackable.
26

OPTIONS

28       preopen:names = /pattern/
29           preopen:names specifies the file name pattern which should trigger
30           the preopen helpers to do their work. We assume that the files are
31           numbered incrementally. So if your file names are numbered
32           FRAME00000.frm FRAME00001.frm and so on you would list them as
33           preopen:names=/FRAME*.frm/
34
35       preopen:num_bytes = BYTES
36           Specifies the number of bytes the helpers should speculatively
37           read, defaults to 1.
38
39       preopen:helpers = NUM-PROCS
40           Number of forked helper processes, defaults to 1.
41
42       preopen:queuelen = NUM-FILES
43           Number of files that should be speculatively opened. Defaults to
44           the 10 subsequent files.
45

VERSION

47       This man page is part of version 4.8.3 of the Samba suite.
48

AUTHOR

50       The original Samba software and related utilities were created by
51       Andrew Tridgell. Samba is now developed by the Samba Team as an Open
52       Source project similar to the way the Linux kernel is developed.
53
54       The PREOPEN VFS module was created with contributions from Volker
55       Lendecke and the developers at IBM.
56
57
58
59Samba 4.8.3                       10/30/2018                    VFS_PREOPEN(8)
Impressum