vidio(1) vidio(1)
NAME
vidiomap - Video frame allocation inspector and resequencer
SYNOPSIS
vidiomap [options] target_dir [target_dir...]
DESCRIPTION
The vidiomap utility can be used to determine how the StorNext file
system has allocated the files within a given directory. Optionally,
vidiomap can be used to "defragment" and "resequence" those files. Op-
tionally, multiple target directories may be specified.
The vidiomap utility is intended to be used primarily on video frame
files within a directory. It is not indented for use as a general pur-
pose file system allocation analysis or "defragmentation" utility. See
snfsdefrag(1).
Without options, vidiomap will print a summary analysis of the alloca-
tion of files in the target directory, including the number of regular
files, the total number of extents, and space consumed. Also printed
is information relating to the total number and average size of the
gaps between the extents.
The -v option may be used to provide detailed information about file
allocation on a per extent basis. The actual file system block numbers
consumed are printed along with the gaps between extents. Notice that
gaps can be negative, indicating the sebsequent allocation was to a
lesser file system block number than the current allocation.
To analyze the allocation of files within a directory, the desired file
order first must be determined. By default, vidiomap will sort all the
files in the target directory alpha-numerically by file name. Option-
ally, file names may be filtered by file prefix and file suffix. See
the -p and -s options. Optionally, a list of file names may be provid-
ed. See the -f option.
The "resequencing" and "defragmentation" of files is a multi-step
process that makes heavy use of the StorNext file System Application
Programming Interface, SNAPI. The steps are a follows:
1. Determine the file order.
2. For each file, a "shadow file" is created and blocks are preallocated.
3. The data is coppied from the original file, to the shadow file.
4. The newly allocated extents are swapped into the original file inode.
5. The "shadow files" are removed.
Shadow files are named filename_shadow and are created in the target
directory.
As stated previously, vidiomap is not a general purpose file system
"defragmentor". An older file system or a file system nearing capacity
may have a fragmented free space pool. Using vidiomap to resequence
files may not help in this case and could make fragmentation worse.
Consider using snfsdefrag before resequencing files with vidiomap.
The resequencing option is intended to work with the StorNext Alloca-
tion Session Reservation feature. This feature is managed using the
GUI or by modifying the AllocSessionReservationSize parameter, see
snfs_config(5).
Because resequencing copies the data to the newly allocated space, con-
sider the performance impact of resequencing files on a production sys-
tem. Resequencing a large number of files can take some time, depend-
ing on the size of the files, the performance of the underlying stor-
age, and other file system activity.
OPTIONS
-? Display usage.
-d[dd] Run in debug mode. The more "d's" specified, the more debug in-
formation is printed.
-f file_list
Get the list of target files from the specified file instead of
the the target directory. The files will be processed in the
order listed. The format for this file is one file name per
line.
-p prefix
Target only files with the specified prefix. If the prefix op-
tion is specified along with the suffix option, both must be
true to target a given file.
-r Resequence and "defragment" the target files.
-s suffix
Target only files with the specified suffix. If the prefix op-
tion is specified along with the suffix option, both must be
true to target a given file.
-v Be verbose. Print each extent of each target file showing the
file system blocks consumed and gaps between the extents.
FILES
/System/Library/Filesystems/acfs.fs/Contents/bin/vidiomap
SEE ALSO
cvfs(8), snfsdefrag(1), snfs_config(5), vidio(1)
StorNext File System June 2014 vidio(1)
Mac OS X 10.12.3 - Generated Sat Feb 4 18:21:42 CST 2017