•Evaluación y presupuesto de la mercadotecnia •Plan de mercadotecnia
V. Formulación de estrategias
The other major function that DFSMShsm provides is availability management. Availability management enables a user to recover a lost or damaged data set easily. A storage administrator can recover a damaged volume easily at the current level.
Availability management (backup) automatically and periodically performs the following backups:
Back up CDSs and journal DFSMShsm
Back up data sets from DASD to tape volumes
Back up changed data sets on DASD volumes to other DASD or tape volumes
Back up data sets of an application to tape volumes so they can be taken offsite for recovery
By performing these functions, automatic backup can help in these ways:
Prevent users from accidentally losing or incorrectly changing data sets
Recover data after a volume is lost due to a hardware failure
Protect against loss of data due to a disaster
Ensure that critical data is retained
New data retention laws cause an increased need for backups of critical data. The following functions provide valid backup or dump copies so that you can recover:
Backup
Dump
Aggregate backup and recovery support (ABARS)
Fast replication backup
1.7.1 Backup and recovery
Different methods are available to back up your data. DFSMShsm provides an automatic backup function, inline backup, fast replication backup, and aggregate backup.
Automatic backup
The
autobackup
function is a data-set-level function. It relies on the guaranteed backup frequency attribute of the storage group for each data set to determine whether to copy the data set. After a data set is backed up, this function uses the data set’s management class attributes to decide how the data set is treated for the creation and retention of backup versions (how many backup versions are kept and how long they are kept).In a non-SMS environment, the backup frequency is defined for the entire volume. All data sets that changed since the last backup process ran are eligible for a new backup.
Recovery restores data sets from the daily backup volumes or the spill backup volumes to the level 0 volumes. Recovery can be performed only by command, for individual data sets or complete volumes.
Inline backup
With the
inline backup
function, you can back up data sets in a batch or online environment. You can back up data sets in the middle of a job in a batch environment, or directly through Time Sharing Option (TSO). Inline backup writes the backup version on an ML1 volume or to a tape volume. If the data set is moved to an ML1 volume, you can minimize unplanned tape mounts. In that case, the backup version is later moved to the backup volume duringautomatic backup or by command.
ABARS
Aggregate backup and recovery support (ABARS) is a function of DFSMShsm that is designed for use in disaster recovery. ABARS facilitates a point-in-time backup of a collection of related data in a consistent manner. This group of related data is defined to ABARS as an aggregate. An aggregate is user-defined and usually a collection of data sets that are related, such as all of the specific data sets required for an application (for example, payroll). ABARS backs up the data directly from DASD (either SMS-managed or non-SMS-managed),
DFSMShsm-owned ML1 DASD, or DFSMShsm-owned ML2 tape without needing intermediate staging capacity. The backup copies are created in a device-independent format.
ABARS can be used also for moving applications across non-sharing systems. If ABARS is used as a disaster recovery tool, at the recovery site, it is used to recover the data sets and allocates user-defined empty data sets that the client requires for their operating environment. The aggregate backup and aggregate recovery functions provide the capability to back up and recover a user-defined group of data sets. The user-defined group of data sets can belong to an application or any combination of data sets that you want treated as a separate entity. ABARS treats SMS and non-SMS data sets identically.
With the aggregate backup and aggregate recovery functions, you can perform the following actions:
Define the components of an aggregate
Back up data sets by aggregate
Recover data sets by aggregate
Recover a single data set
Duplicate your aggregates at a remote site
Chapter 1. DFSMShsm overview 15
Fast replication
Fast replication is a function that uses volume-level fast replication to create backup versions for sets of storage groups. You can define a set of storage groups with the SMS copy pool construct. Fast replication target volumes contain the fast replication backup copies of volumes that are managed by DFSMShsm. Fast replication target volumes are defined with the SMS copy pool backup storage group type.
The DFSMShsm FRBACKUP command creates a fast replication backup version for each volume in every storage group that is defined within a copy pool. Volumes that have a fast replication backup version can be recovered either individually or at the copy pool level with the DFSMShsm FRRECOV command. This function enables the backup and recovery of a large set of volumes to occur within a short time frame. For more information about fast replication and its requirements, see the DFSMShsm Fast Replication Technical Guide, SG24-7069.
1.7.2 Dump
By using the automatic full volume dump function with the automatic incremental backup, the storage administrator can recover a complete volume by restoring the volume from the full volume dump, then correcting the volume for later activity by the automatic inclusion of changes taken from incremental backups. A DFSMShsm-authorized user can issue one
RECOVER command that is used to request both a volume restore and an incremental volume recovery.
To use the dump function, a dump class must be assigned to the required storage groups. Next, you need to define the dump class to DFSMShsm if it is not already set. The dump class definition includes a brief description, the dump date or day of the week to be dumped, the retention period, and the expiration date.