1. DS6000/DS8000 FlashCopy in z/OS Environments Quick Reference
What is FlashCopy?
FlashCopy® is an “instant” T0 (Time 0) copy where the source and target volumes are immediately available for processing with full r/w access after the relationship has been established. It is a hardware solution that is software invoked. FlashCopy can be invoked by DFSMSdss, TSO, ICKDSF, z/OS API, DS CLI, and the DS Storage Manager (GUI). Open environments typically use DS CLI or TPC for replication.
The FlashCopy source is a set of tracks that can consist of an entire volume or just a selected set of tracks.
Request copy from source to target
FlashCopy relationship created
Target available for r/w
BACKGROUND COPY/NOCOPY
Tracks copied from source to target
COPY copies all tracks
NOCOPY copies tracks updated on source
Attempts to r/w data already copied
Read/write to volume I/O is issued to
Attempts to read a target track not already copied obtains data from source
Attempts to write a source track not already copied is intercepted and source track copied to target before update occurs
Note: BACKGROUND COPY will physically copy all tracks from source to target while NOCOPY will only physically copy tracks that are updated on the source.
Types of FlashCopy in System z
The following commands are shown in the following order. First for DFSMSdss, then TSO, and finally ICKDSF. Only DFSMSdss serializes resources.
Full volume COPY and NOCOPY
Data on the entire volume is available for r/w on both the source and target. COPY will physically copy all source tracks to target and NOCOPY will only physically copy updated tracks on source.
COPY FULL INDD(DASD1) OUTDD(DASD2) ADMIN DUMPCONDITIONING
COPY FULL INDD(DASD1) OUTDD(DASD2) -FCNOCOPY ADMIN DUMPCONDITIONING
FCESTABL SDEVN(X’uadd’) TDEVN(X’uadd’)
FCESTABL SDEVN(X’uadd’) TDEVN(X’uadd’) MODE(NOCOPY)
FLASHCPY ESTABLISH DDNAME(ddname) – TARGETVOL(lss,cca,cuuu)
FLASHCPY ESTABLISH DDNAME(ddname) -TARGETVOL(lss,cca,cuuu) MODE(NOCOPY)
Data set FlashCopy
Only for z/OS™ using DFSMSdss.
Background NOCOPY to COPY
Although it is a remove flash command, the relationship is maintained and starts the BACKGROUND COPY.
COPY FULL INDD(DASD1) OUTDD(DASD2) FCNOCOPYTOCOPY
FCESTABL SDEVN(X’uadd’) TDEVN(X’uadd’) - FCNOCOPYTOCOPY
Persistent FlashCopy
A persistent relationship is maintained even after the BACKGROUND COPY completes otherwise it would be withdrawn. To remove a persistent relationship, manually withdraw it.
There is no single persistent parameter when invoking FlashCopy in a System z environment. But, persistent is used automatically when establishing an Incremental FlashCopy or Fast Reverse Restore Enabled (Global Mirror) FlashCopy.
DS6000/DS8000 FlashCopy in z/OS Environments Quick Reference
This document covers:
What is FlashCopy?
Types of FlashCopy in System z™
Invoking FlashCopy functions
Which tool can invoke which function
FlashCopy source and target placement
March 2007
source
target
Reads
Writes
© International Business Machines Corporation, IBM, and FlashCopy are registered trademarks and System z, z/OS, DS6000, and DS8000 are of International Business Machines in the U.S. and other countries. Other company, product, or service names may be trademarks or service marks of others. IBM reserves the right to change specifications or other product information without notice. This publication may include typographic errors and technical inaccuracies. The content is provided as is, without express or implied warranties of any kind, including the implied warranties of merchantability or fitness for a particular purpose.

2. Types of FlashCopy in System z
Multiple relationships
A single source volume can have up to 12 targets, of which only one can be incremental.
Incremental FlashCopy
Incremental FlashCopy provides the capability to only BACKGROUND COPY tracks that have been changed since the last increment was taken. An incremental flash can be performed in either direction. Initial establish:
COPY FULL INDYNAM(VOL00A) OUTDYNAM(VOL00B) DUMPCONDITIONING - ADMIN FCINCREMENTAL
FCESTABL SDEVN(X’uadd’) TDEVN(X’uadd’) – INCREMENTAL(YES)
FLASHCPY ESTABLISH UNIT(F001) – TGTVOL(X’07’,X’01’,F701) – CHANGERECORDING(YES)
To reverse the increment, swap the swap the source and target. To make sure you going in the correct direction using DFSMSdss, specify FCINCRVERIFY(REVERSE).
COPY FULL INDYNAM(VOL00B) OUTDYNAM(VOL00A) DUMPCONDITIONING - ADMIN FCINCREMENTAL – FCINCRVERIFY(REVERSE)
COPY FULL INDYNAM(VOL00B) - OUTDYNAM(VOL00A) DUMPCONDITIONING - ADMIN FCINCREMENTAL – FCINCRVERIFY(REVERSE)
When FCINCREMENTAL, INCREMENTAL, or CHANGERECORDING is specified, persistence is automatically set.
To maintain the incremental relationship, specify recording on each
Inband FlashCopy Inband FlashCopy allows FlashCopy requests to be issued remotely through an existing PPRC link.
FCESTABL DEVN(devno) SOURCE(serialno lss cca|lun) TARGET(serialno lss cca|lun) MODE(COPY) SSID(ssid) REMOTE(YES)
FLASHCPY ESTABLISH UNIT(ccuu) - SOURCEVOL(lss,cca,ser#,ccuu)
Fast Reverse Restore enabled FlashCopy
Typically used in a Global Mirror environment.
FCESTABL SDEVN(ssss) TDEVN(tttt) MODE(ASYNC)
FLASHCPY ESTABLISH UNIT(ccuu) -TARGETVOL(lss,cca,cuuu) - CHANGERECORDING(YES) MODE(NOCOPY) - INHIBITTARGETWRITES(YES)
Fast Reverse Restore
Used to Global Mirror journal back to the Global mirror secondary. Switch the original source and target addresses
FCESTABL SDEVN(ssss) TDEVN(tttt) ACTION(FRR)
Unit is the original target and TARGETVOL is the original source.
FLASHCPY ESTABLISH UNIT(ccuu) -TARGETVOL(lss,cca,cuuu) - FASTREVERSERESTORE TGTOKPRIME(YES)
Consistency group FlashCopy
FlashCopy Consistency Groups provides a mechanism for achieving consistent data copy across multiple volumes and disk subsystems without requiring that application I/O be quiesced.
Once a pair is established, extended long busy is returned to the server when writes are issued preserving the order of dependent writes. The freeze lasts 2 minutes or until the unfreeze command is issued.
COPY FULL INDYNAM(SRC101) -OUTDYNAM(TGT101) ADMIN DUMPCOND - FCCGFREEZE
COPY FULL INDYNAM(SRC102) -OUTDYNAM(TGT102) ADMIN DUMPDOND - FCCGFREEZE
CGCREATE FCCGVFY(SRC101) ACCVOL(SRC101)
FCESTABL SDEVN(X’uadd’) TDEVN(X’uadd’) –ACTION(FREEZE)
FCESTABL DEVN(X’uadd’) SDEVN(X’uadd’) - TDEVN(X’uadd’) ACTION(THAW)
Must use the DEVN parameter on the TSO THAW command. ICKDSF does not support consistency group. Freeze is a volume level command and the THAW command is a LSS level command. Before issuing thaw, make sure that there are no other consistency groups being formed in that LSS.
Which tools invoke which FlashCopy Function?
DSS
TSO
API
DSF
DS CLI
Full volume
Yes
NOCOPY-COPY
Incremental CG No
Persistent only
Inband
FRR Enabled
FRR
Multiple relations
Data Set
FlashCopy source and target placement
Same Cluster
Same DA
SameRank
FlashCopy Establish Performance
Same
Doesn’t matter No
Background Copy Performance
Different
FlashCopy impact to Application