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DB2 UDB for z/OS Version 8 Performance Topics - IBM Redbooks

DB2 UDB for z/OS Version 8 Performance Topics - IBM Redbooks

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5.1 System level point-in-time recovery<br />

Prior to <strong>DB2</strong> V8 you could make an external copy of your production system by delimiting the<br />

back up activity with the -SET LOG SUSPEND and -SET LOG RESUME commands. <strong>DB2</strong>’s update<br />

activity and logging, while you were making the external copy of your <strong>DB2</strong> system, was<br />

suspended.<br />

<strong>DB2</strong> V8 introduces the new BACKUP SYSTEM and RESTORE SYSTEM utilities. This<br />

provides an easier and less disruptive way to make fast volume-level backups of an entire<br />

<strong>DB2</strong> subsystem or data sharing group with minimal disruption, and recover a subsystem or<br />

data sharing group to any point-in-time, regardless of whether or not you have uncommitted<br />

units of work. At <strong>DB2</strong> restart, the uncommitted URs are resolved during the <strong>for</strong>ward and<br />

backward recovery phase.<br />

These new utilities rely on the new Fast Replication in DFSMS 1.5. DFSMS provides a<br />

volume-level fast replication function that allows you to create a backup that is managed by<br />

DFSMShsm with minimal application outage. DFSMShsm recovers a Fast Replication backup<br />

version from the volume or copy pool level, but not at the data set level. This function enables<br />

the backup and recovery of a large set of volumes to occur within a small time frame. The<br />

term Fast Replication refers to the FlashCopy function supported by <strong>IBM</strong> TotalStorage®<br />

Enterprise Storage Server® (ESS) disk and the SnapShot function supported by <strong>IBM</strong><br />

RAMAC® Virtual Array (RVA) disk.<br />

► The BACKUP SYSTEM utility provides fast volume-level copies (versions) of <strong>DB2</strong><br />

databases and logs.<br />

► The RESTORE SYSTEM utility recovers a <strong>DB2</strong> system to an arbitrary point-in-time.<br />

RESTORE SYSTEM automatically handles any creates, drops, and LOG NO events that<br />

might have occurred between the backup and the recovery point-in-time.<br />

Prerequisites <strong>for</strong> this feature<br />

In order to use the BACKUP SYSTEM and RESTORE SYSTEM utilities, all data sets that you<br />

want to back up and recover must be SMS-managed data sets. Additionally, you must have<br />

the following requirements:<br />

► z/<strong>OS</strong> V1R5, DFSMShsm, DFSMSdss.<br />

► Disk control units that support ESS FlashCopy API (we recommend FlashCopy V2).<br />

► SMS copy pools that are defined by using the <strong>DB2</strong> naming convention.<br />

► Defined SMS copy pool backup storage groups.<br />

► <strong>DB2</strong> has to be running in new-function mode.<br />

RESTORE SYSTEM LOGONLY option has no dependency on z/<strong>OS</strong> 1.5.<br />

A copy pool is a set of SMS-managed storage groups that can be backed up and restored<br />

with a single command.<br />

A copy pool backup is a new storage group type that is used as a container <strong>for</strong> copy pool<br />

volume copies. Each volume in the copy pool storage group needs to have a corresponding<br />

volume in the copy pool backup storage group. For each copy pool volume as many backup<br />

volumes as backup versions defined <strong>for</strong> the copy pool should be available in the copy pool<br />

backup.<br />

Each <strong>DB2</strong> system has up to two copy pools, one <strong>for</strong> databases and one <strong>for</strong> logs. The name of<br />

each copy pool that is to be used with <strong>DB2</strong> must use the following naming conventions:<br />

DSN$locn-name$cp-type<br />

The variables that are used in this naming convention have the following meanings:<br />

218 <strong>DB2</strong> <strong>UDB</strong> <strong>for</strong> z/<strong>OS</strong> <strong>Version</strong> 8 Per<strong>for</strong>mance <strong>Topics</strong>

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