mvfscache

Controls and monitors MVFS caches (dynamic views only)

APPLICABILITY

SYNOPSIS

• Determine cache status:

mvfscache [ cache_name ]

• Control cache operation:

mvfscache { -e cache_list | -d cache_list | -f cache_list }

• Display name cache contents:

mvfscache -p [ -n name ] [ -v dbid ] [ -i ]

DESCRIPTION

NOTE: This utility is not intended for general use. It is intended primarily to help ClearCase engineering and Rational Technical Support personnel diagnose problems with the MVFS. For information on user-level cache commands, see the getcache and setcache reference pages.

mvfscache manipulates a dynamic view host's MVFS caches, which are used to optimize file system performance.

RESTRICTIONS

Identities: No special identity is required to flush a cache. To enable or disable a cache, you must have one of the following identities:

• root (UNIX)

• Local Windows system administrator (Windows)

• Member of the Windows Administrators group (Windows)

Locks: No locks apply.

Mastership: (Replicated VOBs only) No mastership restrictions.

OPTIONS AND ARGUMENTS

DETERMINING CACHE STATUS.  With no options or arguments, mvfscache displays the enabled/disabled status of all MVFS caches. If you don't use any of the options, but specify a cache name as an argument, mvfscache does not display any output; it returns an appropriate exit status:

CONTROLLING CACHE OPERATION.  Use one of the following options to control a cache, a set of caches, or cache-related behavior.

-e cache-list

(Must be root (UNIX) or Administrator (Windows)) Enables the specified caches and (with cto) cache-related behavior. Descriptions of these caching parameters are in the Administrator's Guide. The cache-list must be comma-separated, with no white space, and can include one or more of the following keywords.

attr	Attribute cache. Caches information on recently accessed file-system objects.
name	Name cache. Caches name lookup translations for recently accessed files and directories.
slink	Symbolic link text cache. Caches the contents of recently accessed symbolic links.
rvc	VOB root version cache. Caches VOB mount point data for each dynamic view.
cto	(cache-related behavior) Close-to-open consistency behavior. Forces a "get file info"-type operation to the view_server on every operating-system open operation. Disabling this behavior may boost performance if mvfsstat or mvfstime shows heavy cto activity and the user is not sharing views. However, disabling this behavior may result in consistency loss.

-d cache-list

(Must be root (UNIX) or Administrator (Windows)) Disables the specified caches and cache-related behavior. The syntax is the same as for -e.

-f cache-list

Flushes the specified caches. Use this option only under direction from Rational Technical Support. The cache-list can include any number of the following keywords; the list must be comma-separated, with no white space.

mnode	Mnode freelist cache. Flushes the attr and slink caches, open freelist files, and mnode storage for all freelist mnodes.
name	Name cache.
rvc	VOB root version cache.
lcred	Global credentials cache for cleartext lookup permissions.

DISPLAYING NAME CACHE CONTENTS.  Use -p by itself or with one or more of -n, -v, and -i. The name cache contains the name lookup translations for recently accessed files and directories. The first line of a name lookup translation has this form:

-p

Prints the contents of the name cache.

-n name

Prints only the entries in the name cache that match name.

-v dbid

Prints only the entries in the name cache that match directory-dbid (database-ID for the directory in which name is found) or lookup-dbid (database-ID for the result of the lookup).

-i

Includes invalidated name cache entries in the output. These are entries that have been marked bad and are not used in lookups, but are retained for statistical purposes. This helps determine how often invalid entries are replaced with new data. Invalidations usually happen when cleartool or clearmake changes something in the VOB and knows that the MVFS needs to refetch that information for its cache.

EXAMPLES

• Determine the status of all caches.

mvfscache
Attr: on
Name: on
Rvc: on
Slink: on
Cto: on

• Clear busy mount points, to prepare for unmounting VOBs.

mvfscache -f mnode

• Enable the name and attr caches:

mvfscache -e name,attr

SEE ALSO

mvfslog, mvfsstat, mvfsstorage, mvfstime, mvfsversion, csh(1), stat(2)