A partial-state file feature capability that allows you to access the beginning of an offline file before the entire file has been recalled
A valid daemon database entry. See also soft-deleted database entry and hard-deleted database entry.
A source of additional volumes for a volume group that runs out of media. An allocation group defines a logical pool of volumes, and is different from an actual operational volume group. Normally, one allocation group is configured to serve multiple volume groups. If a volume group has an associated allocation group, when the volume group runs out of empty volumes, the LS assigns one from the allocation group to it, subject to configuration restrictions. Similarly, when a volume's hfree flag is cleared in a volume group, it is returned to the allocation group, subject to configuration restrictions. The use of allocation groups is optional. Allocation groups are defined in the DMF configuration file (/etc/dmf/dmf.conf).
The media onto which migrated data blocks are stored, usually tapes.
The combination of utilities that allows DMF to maintain a specified level of free space on a filesystem through automatic file migration.
The configuration object that defines pathname and file size parameters necessary for DMF operation.
See bit-file identifier (BFID)
See bit file identifier.
A unique identifier, assigned to each file during the migration process, that links a migrated file to its data on alternate media.
The collection of database entries and the user file associated with a particular BFID.
The sum of the states of the components that comprise a BFID set: the file state of any user file and the state of any database entries (incomplete, complete, soft-deleted, or active).
Physical unit of I/O to and from media, usually tape. The size of a block is determined by the type of device being written. A tape block is accompanied by a header identifying the chunk number, zone number, and its position within the chunk.
A list that contains an entry for each file in a filesystem eligible for migration, or for a file or range of a file eligible for making offline, ordered from largest file weight (first to be migrated) to smallest. This list is generated and used internally by dmfsmon(8). The dmscanfs(8) command prints similar file status information to standard output.
The catalog (CAT) records in the LS database that track which migrated files reside on which tape volumes.
That portion of a user file that fits on the current media (tape) volume. Most small files are written as single chunks. When a migrated file cannot fit onto a single volume, the file is split into chunks.
An entry in the daemon database whose path field contains a key returned by its MSP or volume group, indicating that the MSP or volume group maintains a valid copy of the user file.
The mechanism provided by the LS for copying active data from volumes that contain largely obsolete data to volumes that contain mostly active data. This process is also known as volume merging or tape merging.
A series of parameter definitions in the DMF configuration file that controls the way DMF operates. By changing the parameters associated with objects, you can modify the behavior of DMF.
A string in the DMF configuration file that defines a part of a configuration object. By changing the values associated with these parameters, you can modify the behavior of DMF. The parameter serves as the name of the line. Some parameters are reserved words, some are supplied by the site.
A database maintained by the DMF daemon. This database contains such information as the BFID, the MSP or volume group name, and MSP or volume group key for each copy of a migrated file.
The configuration object that defines parameters necessary for dmfdaemon(8) operation
The portion of the inode that points to the file's data blocks.
The configuration object that defines parameters for the DMF backup scripts' use of tape devices other than those defined by a drive group.
An IBM disk drive.
The feature that lets you configure the disk MSP to manage data on secondary storage, allowing you to further migrate the data to tape as needed.
See drive group.
See file state.
One of the components of an LS. The drive group is responsible for the management of a group of interchangeable tape drives located in the tape library. These drives can be used by multiple volume groups and by non-DMF processes, such as backups and interactive users. However, in the latter cases, the drive group has no management involvement; the mounting service (TMF or OpenVault) is responsible for ensuring that these possibly competing uses of the tape drives do not interfere with each other.The main task of the drive group is to monitor tape I/O for errors, attempt to classify them as volume, drive, or mounting service problems, and to take preventive action.
In DCM, a cache-resident copy of a migrated file that has already been copied to tape, and can therefore be released quickly in order to prevent the cache filling, without any need to first copy it to tape (analogous to a dual-state file)
A file whose data resides both online and offline.
Those filesystems that have the necessary inode space to support dual-state files.
See file handle.
An inode and its associated data blocks; an empty file has an inode but no data blocks.
The DMAPI identification for a file. You can use the dmscanfs(8), dmattr(1), and dmfind(1) commands to find file handles.
The migration state of a file as indicated by the dmattr(1) command. A file can be regular (not migrated), migrating, dual-state, offline, partial-state, unmigrating, never-migrated, or have an invalid DMF state.
A site-assigned 16-bit integer associated with a specific file allowing the file to be identified and acted upon.
A user file that has been migrated and whose data blocks have been released.
A file that has one or more complete offline copies and no pending or incomplete offline copies.
An MSP or volume group database entry that has been removed from the daemon database and whose MSP or volume group copy has been discarded. See also active database entry and soft-deleted database entry.
The portion of a file that contains the BFID, the state field, and the data pointers.
An entry in the daemon database for an MSP or volume group that has not finished copying the data, and therefore has not yet returned a key. The path field in the database entry is NULL.
A file that has begun the migration process, but for which one or more copies on alternate media have not yet been made.
The daemon-like process by which data blocks are copied onto tape and which maintains the location of the migrated data. Each LS has an associated catalog (CAT) and volume (VOL) database. An LS can be configured to contain one or more drive groups. Each drive group contains one or more volume groups. A volume group is responsible for copying data blocks onto alternate media. A volume group is capable of managing a single copy of a user file.
See library server
The daemon-like process by which data blocks are copied onto alternate media, and which assigns keys to identify the location of the migrated data.
The mechanism provided by the LS for copying active data from volumes that contain largely obsolete data to volumes that contain mostly active data. This process is also known as volume merging or tape merging.
A file that has a BFID and whose offline copies (or copy) are completed. Migrated files can be dual-state or offline.
A file that has a BFID but whose offline copies (or copy) are in progress.
See media-specific process (MSP).
The daemon database entry for a file that contains the path or key that is used to inform a particular MSP or volume group where to locate the copy of the file's data.
The configuration object that defines parameters necessary for that MSP's operation. There is one MSP object for each MSP.
A file that does not have a BFID or any offline copies. See regular file.
A file whose inode contains a BFID but whose disk blocks have been removed. The file's data exists elsewhere in copies on alternate media.
In MSP and volume group processing, a character string that the MSP or volume group returns to the daemon to indicate how a file is to be retrieved.
Unused chunks in the LS catalog (CAT) database entries resulting from the removal of migrated files.
Unused database entries resulting from the removal of migrated files during a period in which the DMF daemon is not running.
A partial-state file feature capability that allows you to keep a specific region of a file online while freeing the rest of it (for example, if you wanted to keep just the beginning of a file online). See also partial-state file.
A file that has more than one region. DMF allows a file to include up to four distinct file regions. See also region .
A partial-state file feature capability that allows you to recall a specific region of a file without recalling the entire file. For more information, see the dmput(1) and dmget(1) man pages. See also partial-state file.
See configuration parameter.
The configuration objects that specify parameters to determine MSP or volume group selection, automated space management policies, and/or file weight calculations in automatic space management.
To request that a migrated file's data be moved back (unmigrated) onto the filesystem disk, either by explicitly entering the dmget(1) command or by executing another command that will open the file, such as the vi(1) command.
A contiguous range of bytes that have the same residency state. The states can be DUALSTATE, OFFLINE , MIGRATING, or UNMIGRATING.
DMF considers a regular file to be one with no BFID and no offline copies.
A site-specific library of C++ functions that DMF will consult when making decisions about its operation.
The information about all BFID sets that is collected and analyzed by dmaudit(8). The snapshot analysis is available from the report function.
A daemon database entry for which the MSP or volume group copy of the data is no longer valid. Data remains on the alternate media until the database entry is hard-deleted. See also active database entry and hard-deleted database entry .
A tape containing only a small amount of active information.
UNIX special files are never migrated by DMF.
The field in the inode that shows the current migration state of a file.
See block.
See chunk.
A process initiated by the DMF event mechanism. Configuration tasks that allow certain recurring administrative duties to be automated are defined with configuration file parameters.
A file that the daemon will never select as a migration candidate.
See recall.
See volume group
A BFID-set state that consists of one or more soft-deleted daemon database entries, either incomplete or complete. There is no user file.
The process of removing the BFID from the user file inode and soft-deleting all associated database entries.
The volume (VOL) records in the LS database that contain information about each tape volume that exists in the pool of tapes used by the LS.
One of the components of an LS. A volume group is responsible for copying data blocks onto alternate media. Each volume group contains a pool of tapes, all of the same media type, capable of managing single copies of user files. Multiple copies of the same user files require the use of multiple volume groups. See also library server (LS) .
The mechanism provided by the LS for copying active data from volumes that contain largely obsolete data to volumes that contain mostly active data.
A logical grouping of chunks. Zones are separated by file marks and are the smallest block-addressable unit on the tape volume. The target size of a zone is configurable by media type.