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- testing 2:4.21.2+dfsg-3
- unstable 2:4.21.2+dfsg-4
- experimental 2:4.21.2+dfsg-4~exp1
VFS_PREOPEN(8) | System Administration tools | VFS_PREOPEN(8) |
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:posix-basic-regex = BOOL (default: no)
preopen:names = /pattern1/pattern2/
preopen:posix-basic-regex = yes changes the meaning of the preopen:names option. It means 'POSIX Basic Regular Expression' strings are used as patterns. The key is each pattern requires exactly one 'subexpression' starting with '\(' and ending with '\)' in order to specify the position of the digits representing the incrementing frame numbers. Given a file names like Movie7599Frame0v1234.txt, Movie7599Frame1v1234.txt, Movie7599Frame2v1234.txt up to Movie7599Frame9v1234.txt you can use preopen:names = /.*Frame\([0-9]\).*\.txt/ in order to match just a single digits, this might not be a real world example, but it shows the flexibility that is possible here.
preopen:num_bytes = BYTES
preopen:helpers = NUM-PROCS
preopen:queuelen = NUM-FILES
preopen:nomatch_log_level = LOGLEVEL
Defaults to the log level 5. See also smb.conf(5) in the 'log level' section for special handling of the 'preopen' debug class.
preopen:match_log_level = LOGLEVEL
See also 'preopen:founddigits_log_level' and 'preopen:push_log_level'.
Defaults to the log level 5. See also smb.conf(5) in the 'log level' section for special handling of the 'preopen' debug class.
preopen:nodigits_log_level = LOGLEVEL
Defaults to the log level 1. See also smb.conf(5) in the 'log level' section for special handling of the 'preopen' debug class.
preopen:founddigits_log_level = LOGLEVEL
Defaults to the log level 3. See also smb.conf(5) in the 'log level' section for special handling of the 'preopen' debug class.
preopen:reset_log_level = LOGLEVEL
Defaults to the log level 5. See also smb.conf(5) in the 'log level' section for special handling of the 'preopen' debug class.
preopen:push_log_level = LOGLEVEL
Defaults to the log level 3. See also smb.conf(5) in the 'log level' section for special handling of the 'preopen' debug class.
preopen:queue_log_level = LOGLEVEL
Defaults to the log level 10. See also smb.conf(5) in the 'log level' section for special handling of the 'preopen' debug class.
VERSION¶
This man page is part of version 4.21.2-Debian-4.21.2+dfsg-4 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.
12/01/2024 | Samba 4.21.2-Debian-4.21.2+dfs |