mkpool

Creates a VOB storage pool or modifies its scrubbing parameters

APPLICABILITY


Product

Command Type

ClearCase


cleartool subcommand


Attache


command


Platform

UNIX


Windows

SYNOPSIS

UNIX only-mkpool -sou·rce [ -ln pname ]

[ -c·omment comment | -cfi·le comment-file-pname |-cq·uery | -cqe·ach | -nc·omment ]
pool-selector ...
mkpool { -der·ived | -cle·artext } [ -ln pname ]

[ -siz·e max-kbytes reclaim-kbytes [ -age hours ] [ -ale·rt command ] ]
[ -c·omment comment | -cfi·le comment-file-pname |-cq·uery | -cqe·ach | -nc·omment ]
pool-selector ...
mkpool -sou·rce

[ -c·omment comment | -cfi·le comment-file-pname |-cq·uery | -cqe·ach | -nc·omment ]
pool-selector ...
mkpool { -der·ived | -cle·artext }

[ -siz·e max-kbytes reclaim-kbytes [ -age hours ] [ -ale·rt command ] ]
[ -c·omment comment | -cfi·le comment-file-pname |-cq·uery | -cqe·ach | -nc·omment ]
pool-selector ...
mkpool -upd·ate [ -siz·e max-kbytes reclaim-kbytes ] [ -age hours ] [ -ale·rt command ]

[ -c·omment comment | -cfi·le comment-file-pname |-cq·uery | -cqe·ach | -nc·omment ]
pool-selector ...

DESCRIPTION

The mkpool command creates a source storage pool, derived object storage pool, or cleartext storage pool, and initializes the pool's scrubbing parameters. You can also use this command to update the scrubbing parameters of an existing storage pool.

Storage pools are directories used as physical storage areas for different kinds of data:

Creating a new VOB with the mkvob command creates one default pool of each kind: sdft (source pool), ddft (derived object pool), and cdft (cleartext pool).

mkpool creates a storage pool as a directory within the VOB storage area. Source pools are always created within subdirectory s of the VOB storage directory; derived object pools are created within subdirectory d; cleartext pools are created within subdirectory c. The -ln option allows you to create pools elsewhere, to be accessed at the standard locations through symbolic links.

Pool Allocation and Inheritance

Each file element is assigned to one source pool and one cleartext pool. The source pool provides permanent storage, in one or more data container files, for all of the element's versions. If the element's versions are stored in a compressed format, the cleartext pool is used to cache extracted versions of that element, as described earlier. (If each version is stored uncompressed in a separate data container, the cleartext pool is not used.)

Each directory element is also assigned to one source pool and one cleartext pool. But directory versions themselves are not stored in these pools. (They are stored directly in the VOB database.) Rather, a directory's pool assignments are used solely for pool inheritance: each element created within the directory inherits its source and cleartext pool assignments.

Each directory element is also assigned to one derived object pool. All shared derived objects with pathnames in that directory are stored in that pool. A new directory element inherits the derived object pool of its parent, along with the source and cleartext pools.

The pool inheritance scheme begins at the VOB root directory (top-level directory element) created by mkvob, which is automatically assigned to the default pools.

You can change any of an element's pool assignments with the chpool command.

Scrubbing

Scrubbing is the process of reclaiming space in a derived object pool or cleartext pool. (Source pools are not subject to scrubbing.) This process is performed by the scrubber utility. mkpool initializes or updates these scrubbing parameters:

maximum size

(max-kbytes) Maximum pool size

reclaim size

(reclaim-kbytes) Size to which scrubber attempts to reduce the pool

age

(hours) Threshold to prevent premature scrubbing of recently referenced objects

The default settings for the scrubbing parameters are max-kbytes = 0, reclaim-kbytes = 0, hours = 96. See the scrubber reference page for details on how these parameters are interpreted.

By default, the scheduler runs scrubber periodically. See the schedule reference page for information on describing and changing scheduled jobs.

Getting Information on Storage Pools

The lspool command lists a VOB's storage pools. If you include the -long option, the current settings of the scrubbing parameters are listed, as well. (The describe -pool command displays the same information as lspool -long.)

RESTRICTIONS

Identities: You must have one of the following identities:

Locks: An error occurs if one or more of these objects are locked: VOB, pool (for -update only).

Mastership: (Replicated VOBs only) No mastership restrictions.

OPTIONS AND ARGUMENTS

SPECIFYING THE KIND OF STORAGE POOL / SPECIFYING AN UPDATE.  Default: You must specify the kind of pool, unless you use -update and name an existing pool. The following options are mutually exclusive.

-sou·rce

Creates a source pool.
-der·ived

Creates a derived object pool.
-cle·artext

Creates a cleartext pool.
-upd·ate

Asserts that the parameters of an existing pool are to be updated. You must also use a -size and/or -age option.

LOCAL VS. REMOTE STORAGE.  Default: Creates a storage pool as a subdirectory under the VOB storage directory.

-ln pname

Creates a storage pool directory at pname, and creates pool-name in the VOB storage directory as a symbolic link to pname. You can create only one pool when using this option.
RESTRICTION: pname must be a full pathname, starting with a slash (/). It must also be a global pathname, valid on every host from which users will access the VOB. mkpool attempts to verify that this pathname is truly global, using a simple heuristic. (For example, a pathname that begins with /net is likely to be global.) If it suspects that pname is not global, mkpool proceeds anyway, but displays a warning message:
Warning: Linktext for pool does not appear to be a global path.
This mechanism is independent of the network storage registry facility. Thus, the pathname to a remote storage pool directory must be truly global, not global within a particular network region.
CAUTION: We recommend that you keep source pools local, within the VOB storage directory. This strategy optimizes data integrity: a single disk partition contains all of the VOB's essential data. It also simplifies backup/restore procedures.

SPECIFYING NEW PARAMETERS.  Default: For a new derived object or cleartext pool: the maximum size and reclaim size parameters are set to 0, which enables a special scrubbing procedure. (See the scrubber reference page.) The age parameter is set to 96 (hours). These parameters are meaningless for a source pool.

When updating an existing pool, you must use at least one of -size and -age.

-siz·e max-kbytes reclaim-kbytes

Specifies that the pool is scrubbed if its size exceeds max-kbytes KB; scrubbing will continues until the pool reaches the goal size of reclaim-kbytes KB.
-age hours

Prevents scrubbing of derived objects or cleartext files that have been referenced within the specified number of hours. Specifying -age 0 restores the default age setting (96 hours).

SCRUBBER FAILURE PROCESSING.  Default: If scrubber fails to scrub a pool below its max-kbytes level, it logs a warning message in /var/adm/atria/log/scrubber_log (UNIX) or the Windows event log, but takes no other action.

-ale·rt command

Causes scrubber to run the specified command (typically, a shell script or batch file) whenever it fails to scrub a pool below its max-kbytes level.
WINDOWS: If you invoke a command built in to the Windows shell (for example, cd, del, dir, or copy) instead of a batch file, you must invoke the shell with cmd /c. For example:
-alert 'cmd /c cd \tmp & del *.*'

EVENT RECORDS AND COMMENTS. Default: Creates one or more event records, with commenting controlled by your .clearcase_profile file (default: -cqe). See the comments reference page. Comments can be edited with chevent.

-c·omment comment | -cfi·le comment-file-pname |-cq·uery | -cqe·ach | -nc·omment

Overrides the default with the option you specify. See the comments reference page.

SPECIFYING THE POOL.  Default: Creates or updates a pool in the VOB containing the current working directory unless you specify another VOB with the @vob-selector suffix.

pool-selector ...

One or more names for the storage pools to be created. Specify pool-selector in the form [pool:]pool-name[@vob-selector]

pool-name

Name of the storage pool

See the cleartool reference page for rules about composing names.

vob-selector

VOB specifier

Specify vob-selector in the form [vob:]pname-in-vob

pname-in-vob

Pathname of the VOB-tag (whether or not the VOB is mounted) or of any file-system object within the VOB (if the VOB is mounted)

EXAMPLES

The UNIX examples in this section are written for use in csh. If you use another shell, you may need to use different quoting and escaping conventions.

The Windows examples that include wildcards or quoting are written for use in cleartool interactive mode. If you use cleartool single-command mode, you may need to change the wildcards and quoting to make your command interpreter process the command appropriately.

In cleartool single-command mode, cmd-context represents the UNIX shell or Windows command interpreter prompt, followed by the cleartool command. In cleartool interactive mode, cmd-context represents the interactive cleartool prompt. In Attache, cmd-context represents the workspace prompt.

SEE ALSO

chpool, find, lspool, mkvob, schedule, scrubber