DASD fast replication backup without background copy

We describe how to use copy pools that are defined to hold 0 (zero) fast replication DASD backup versions with background copy. By using this type of copy pools, you can create backups on target volumes that are FlashCopy Space Efficient (SE) volumes or standard volumes (fully provisioned).

When you use a copy pool with zero fast replication DASD backup versions on the

FRBACKUP command, DFSMSdss is always called in NOCOPY mode. No option is available on the command level to override this setting.

Whether you can use a NOCOPY fast replication DASD backup version for restore from DASD is determined by the setting of the ALLOW FAST REVERSE RESTORE field in the copy pool:

N You cannot recover from the DASD backup copy.

Y This value enables recoverability from the DASD backup. You cannot create an incremental backup in NOCOPY mode because an incremental relationship is always based on a full background copy.

Backup version example

We prepared copy pools CPSE1 and CPSE2 in our lab environment with a VERSIONS value

-- DFSMShsm CONTROL DATASET --COPY POOL--LISTING --- AT 21:52:45 ON 10/10/13 FOR SYSTEM=SC70

COPYPOOL=CP2

ALLOWPPRCP FRB=NO FRR=NO

VERSION VTOCENQ DATE TIME FASTREPLICATIONSTATE DUMPSTATE 005 Y 2010/10/13 21:50:29 RECOVERABLE NONE TOKEN(C)=C'' TOKEN(H)=X'' TOTAL NUM OF VOLUMES=00001,INCREMENTAL=Y,CATINFO=Y,FCFRR=Y,RECOVERYINCOMPLETE=N a

SGNAME SOURCE - TARGET SOURCE - TARGET SOURCE - TARGET SOURCE - TARGET SG1 MHL0A0 - YYDF20

0--- END OF -- COPY POOL -- LISTING ---

Support: Space Efficient FlashCopy is supported in NOCOPY mode only. Space Efficient

To create a new backup version of CPSE1, use the command that is shown in Example 5-18.

Example 5-18 FRBACKUP CP(CPSE1) EXECUTE command

HSEND FRBACKUP CP(CPSE1) EXECUTE

After you issue the FRBACKUP CP EXECUTE command, the related messages appear in the DFSMShsm backup log (Figure 5-17).

Figure 5-17 Excerpt from the DFSMShsm backup log on the execution of FRBACKUP CP(CPSE1)

NOCOPY mode results from the generated keyword FCNOCOPY (FCNC, 1) as part of the DFSMSdss COPY function command. Because the copy pool was defined with ALLOW FAST REVERSE RESTORE=Y, the keyword FCFULLVOLUMERELATION (FCFVR, 2) is mandatory. Otherwise, the resulting DASD backup copy cannot be used for recovery of the copy pool.

A QUERY command that is shown in Example 5-19 checks for active FlashCopy relationships with this copy pool.

Example 5-19 QUERY CP(CPSE1) command

HSEND Q CP(CPSE1)

Typically, the messages that are generated (Figure 5-18 on page 84) show on repeated executions of the QUERY command based on small changes in the value of percent completed (PCT-COMP, a) for the background copy. Application write behavior determines how quickly the value of percent complete grows because, in NOCOPY mode, only updated tracks are copied on the occurrence of the first write.

ARC1801I FAST REPLICATION BACKUP IS STARTING FOR COPY POOL CPSE1, AT 20:49:34 ON 2010/10/12

ARC1827I NONPREFERRED FAST REPLICATION CANDIDATE VOLUME YYDE21 SELECTED FOR L0 VOLUME MLDD20, VERSION=0001, RC=0004 ARC0640I ARCFRTM - PAGE 0001 5695-DF175 DFSMSDSS V1R12.0 DATA SET SERVICES 2010.285 20:49

ARC0640I ARCFRTM - ADR035I (SCH)-PRIME(06), INSTALLATION EXIT ALTERED BYPASS FAC CLASS CHK DEFAULT TO YES ARC0640I ARCFRTM - COPY IDY(MLDD20) ODY(YYDE21) DUMPCOND FR(REQ) PUR ALLX ALLD(*) FCNC -

ARC0640I ARCFRTM - FCSETGTOK(FAIL) - 1

ARC0640I ARCFRTM - FCFVR - 2 ARC0640I ARCFRTM - DEBUG(FRMSG(DTL))

ARC0640I ARCFRTM - ADR101I (R/I)-RI01 (01), TASKID 001 HAS BEEN ASSIGNED TO COMMAND 'COPY '

ARC0640I ARCFRTM - ADR109I (R/I)-RI01 (01), 2010.285 20:49:34 INITIAL SCAN OF USER CONTROL STATEMENTS COMPLETED ARC0640I ARCFRTM - ADR050I (001)-PRIME(02), DFSMSDSS INVOKED VIA CROSS MEMORY APPLICATION INTERFACE

ARC0640I ARCFRTM - ADR016I (001)-PRIME(01), RACF LOGGING OPTION IN EFFECT FOR THIS TASK ARC0640I ARCFRTM - ADR006I (001)-STEND(01), 2010.285 20:49:34 EXECUTION BEGINS

ARC0640I ARCFRTM - ADR241I (001)-DDTFP(01), TARGET VTOC BEGINNING AT 000000000:01 AND ENDING AT 000000000:14 IS OVERLAID ARC0640I ARCFRTM - ADR806I (001)-T0MI (02), VOLUME MLDD20 WAS COPIED USING A FAST REPLICATION FUNCTION

ARC0640I ARCFRTM - ADR006I (001)-STEND(02), 2010.285 20:49:34 EXECUTION ENDS

ARC0640I ARCFRTM - ADR013I (001)-CLTSK(01), 2010.285 20:49:34 TASK COMPLETED WITH RETURN CODE 0000

ARC0640I ARCFRTM - ADR012I (SCH)-DSSU (01), 2010.285 20:49:34 DFSMSDSS PROCESSING COMPLETE. HIGHEST RETURN CODE IS 0000 ARC1805I THE FOLLOWING 00001 VOLUME(S) WERE SUCCESSFULLY PROCESSED BY FAST REPLICATION BACKUP OF COPY POOL CPSE1 ARC1805I (CONT.) MLDD20

ARC1802I FAST REPLICATION BACKUP HAS COMPLETED FOR COPY POOL CPSE1, AT 20:49:34 ON 2010/10/12, FUNCTION RC=0000, MAXIMUM VOLUME RC=0000, CAPTURE CATALOG RC=0000

Figure 5-18 Panel messages about the QUERY CP(CPSE1) command

Fast reverse restore

If the copy pool was defined with an ALLOW FAST REVERSE RESTORE value of Y, FlashCopy relationships are withdrawn only in the following situations:

򐂰 On the next FRBACKUP CP(...) EXECUTE command

򐂰 On successful completion of a FRRECOV CP(...) FROMDASD command

򐂰 On execution of a FRBACKUP CP(...) WITHDRAW command

If the copy pool was defined with an ALLOW FAST REVERSE RESTORE value of N, FlashCopy relationships are withdrawn only in the following situations:

򐂰 On the next FRBACKUP CP(...) EXECUTE command

򐂰 On successful creation of a dump copy by automatic dump or command

򐂰 On execution of a FRBACKUP CP(...) WITHDRAW command

By using the LIST command that is shown in Example 5-20, you can check the status of the fast replication backup copy.

Example 5-20 LIST CP(CPSE1) command

HSEND LI CP(CPSE1)

If the copy pool was defined with an ALLOW FAST REVERSE RESTORE value of Y

,

the output of the LIST command (as shown in Figure 5-19) gives no hint of the NOCOPY mode in use.

Figure 5-19 Output of LIST CP(CPSE1) command

ARC1820I THE FOLLOWING VOLUMES IN COPY POOL CPSE1, VERSION 001, HAVE AN ACTIVE ARC1820I (CONT.) FLASHCOPY BACKGROUND COPY ARC1820I (CONT.) SGNAME FR-PRIMARY FR-BACKUP PCT-COMP ARC1820I (CONT.) SG0 MLDD20 YYDE21 001 a

***

-- DFSMShsm CONTROL DATASET --COPY POOL--LISTING --- AT 17:10:06 ON 10/10/14 FOR SYSTEM=SC70

COPYPOOL=CPSE1

ALLOWPPRCP FRB=NO FRR=NO

VERSION VTOCENQ DATE TIME FASTREPLICATIONSTATE DUMPSTATE 001 Y 2010/10/12 20:49:34 RECOVERABLE NONE TOKEN(C)=C''

TOKEN(H)=X'' TOTAL NUM OF

VOLUMES=00001,INCREMENTAL=N,CATINFO=Y,FCFRR=Y,RECOVERYINCOMPLETE=N

SGNAME SOURCE - TARGET SOURCE - TARGET SOURCE - TARGET SOURCE - TARGET SG0 MLDD20 - YYDE21

If the copy pool was defined with an ALLOW FAST REVERSE RESTORE value of N

,

the output of the LIST command (as shown in Figure 5-20) reports a fast replication status of

NONE because the DASD backup copy cannot be used for recovery.

Figure 5-20 Output of LIST CP(CPSE9) command

In document DFSMShsm Fast Replication Technical Guide (Page 100-103)