cfsadmin Command

AIX Version 4.3 Commands Reference, Volume 1

cfsadmin Command

Purpose

Administers disk space used for caching file systems with the Cache File-System (CacheFS).

Syntax

cfsadmin-c []cache_directory

cfsadmin-d [ all ] cache_directory

cfsadmin-s [ all ] cache_directory

cfsadmin-u []

Description

The cfsadmin command provides the following functions:

cache creation
deletion of cached file systems
Listing of cache contents and statistics
resource parameter adjustment when the file system is unmounted.

For each form of the command, unless the -u flag is specified, you must specify a cache directory, that is, the directory under which the cache is actually stored. A path name in the front file system identifies the cache directory. For the of the command, you must specify a mount point.

You can specify a cache ID when you mount a file system with CacheFS, or you can let the system generate one for you. The -l flag includes the cache ID in its listing of information. You must know the cache ID to delete a cached file system.

Flags

-c	Creates a cache under the directory specified by cache_directory. This directory must not exist prior to cache creation.
-d	Removes the file system whose cache ID you specify and release its resources, or remove all file systems in the cache by specifying cache_directory. After deleting a file system from the cache, you must run the command to correct the resource counts for the cache.
-l	Lists file systems stored in the specified cache, as well as statistics about them. Each cached file system is listed by cache ID. The statistics document resource utilization and cache resource parameters.
-s	Requests a consistency check on the specified file system (or all cachefs mounted file systems). The -s flag only works if the cache file system was mounted with demandconst enabled. Each file in the specified cache file system is checked for consistency with its corresponding file in the back file system. The consistency check is performed file by file as files are accessed. If no files are accessed, no checks are performed. Using this flag does not result in a sudden storm of consistency checks. The -s option is not currently supported in AIX CacheFS.
-u	Updates resource parameters of the specified cache directory. Parameter values can only be increased. To decrease the values, you must remove the cache and recreate it. All file systems in the cache directory must be unmounted when you use this flag. Changes will take effect the next time you mount any file system in the specified cache directory. The -u flag with no -o flag sets all parameters to their default values.

CacheFS Resource Parameters

You can specify the following cacheFS resource parameters as arguments to the -o flag. Separate multiple parameters with commas.

maxblocks=n	Maximum amount of storage space that CacheFS can use, expressed as a percentage of the total number of blocks in the front file system. If CacheFS does not have exclusive use of the front file system, there is no guarantee that all the space the maxblocks parameter allows will be available. The default is 90.
minblocks=n	The minimum amount of storage space, expressed as a percentage of the total number of blocks in the front file system, that CacheFS is always allowed to use without limitation by its internal control mechanisms. If CacheFS does not have exclusive use of the front file system, there is no guarantee that all the space the minblocks parameter attempts to reserve will be available. The default is 0.
threshblocks=n	A percentage of the total blocks in the front file system beyond which CacheFS cannot claim resources once its block usage has reached the level specified by minblocks.The default is 85.
maxfiles=n	Maximum number of files that CacheFS can use, expressed as a percentage of the total number of inodes in the front file system. If CacheFS does not have exclusive use of the front file system, there is no guarantee that all the inodes the maxfiles parameter allows will be available. The default is 90.
minfiles=n	Minimum number of files, expressed as a percentage of the total number of inodes in the front file system, that CacheFS is always allowed to use without limitation by its internal control mechanisms. If CacheFS does not have exclusive use of the front file system, there is no guarantee that all the inodes the minfiles parameter attempts to reserve will be available. The default is 0.
threshfiles=n	A percentage of the total inodes in the front file system beyond which CacheFS cannot claim inodes once its usage has reached the level specified by minfiles. The default is 85.
maxfilesize==n	Largest file size, expressed in megabytes, that CacheFS is allowed to cache. The default is 30.

Note: You cannot decrease the block or inode allotment for a cache. To decrease the size of a cache, you must remove it and create it again with different parameters.

Examples

To create a cache directory named cache, enter:
```
cfsadmin -c /cache
```
To create named /cache1 that can claim a maximum of 60 percent of the blocks in the front file system, can use 40 percent of the front file system blocks without interference by CacheFS internal control mechanisms, and has a threshold value of 50 percent. The threshold value indicates that after CacheFS reaches its guaranteed minimum, it cannot claim more space if 50 percent of the blocks in the front file system are already used.
```
cfsadmin -c -o maxblocks=60,minblocks=40,threshblocks=50 /cache1
```
To change the maxfilesize parameter for the cache directory /cache2 to 2 megabytes, enter:
```
cfsadmin -u -o maxfilesize=2 /cache2
```
To list the contents of a cache directory named /cache3 and provides statistics about resource utilization, enter:
```
cfsadmin -l /cache3
```
To remove the cached file system with cache ID 23 from the cache directory /cache3 and free its resources (the cache ID is part of the information returned), enter:
```
cfsadmin -d 23 /cache3
```
To remove all cached file systems from the cache directory, enter:
```
cfsadmin -d all /cache3
```
To check all filesystems mounted with demandconst enabled for consistency. No errors will be reported if no demandconst filesystems were found. Enter:
```
cfsadmin
```

Related Information

The mount command and fsck_cachefs command.