IBM DS6000 Manual Do Utilizador

IBM System Storage DS6000 Series: Copy Services with IBM System z

Concurrent Copy, application processing is interrupted for only a minimum time while the 
system initializes the Concurrent Copy session. Once Concurrent Copy is active, your 
applications continue to process the data, while it is being backed up using Concurrent Copy.

Concurrent Copy provides point-in-time data consistency. The system serializes access to 
the data being dumped or copied just long enough for the Concurrent Copy session to be 
initialized. This serialization takes a very short time to complete, and this process ensures the 
point-in-time copy will be consistent, while the copy is being done with your applications 
running.

For details about the operation of Concurrent Copy, refer to z/OS DFSMS Advanced Copy 
Services, SC35-0428.

Concurrent Copy (CC) can be invoked by either the DFSMSdss or the DFSMShsm™ 
functions. IMS™, CICS®, DFSMSrmm™, and DB2 can use CC for their backups. 

DFSMSdss has the option of using Concurrent Copy when data sets are copied or dumped. 
To invoke Concurrent Copy, the CONCURRENT keyword must be specified on a DFSMSdss 
COPY or DUMP commands.

With DFSMShsm, system-managed data can be backed up automatically with Concurrent 
Copy by use of management class parameters. DFSMShsm also allows Concurrent Copy to 
be used when copying data using Aggregate Backup and Recovery Support (ABARS). 

Using the CONCURRENT control statement of the DB2 COPY utility, you can invoke 
Concurrent Copy to make a full image copy. During recovery, DB2 can automatically use the 
most recent image copy and then apply records from the log. 

Concurrent Copy requires the software support provided in DFSMS/MVS. For details on 
using Concurrent Copy with these products, refer to the appropriate product manual.

Concurrent Copy is initiated using the CONCURRENT keyword in DFSMSdss or in 
applications that internally call DFSMSdss as the copy program, such as the DB2 COPY 
utility.

The SDM establishes a Concurrent Copy session with the DS6000. There can be up to 64 
sessions active at a time per DS6000 logical subsystem (LSS). 

Concurrent Copy and FlashCopy can coexist in the same DS6000.

If DFSMSdss is instructed to do a Concurrent Copy by specifying the CONCurrent (CC) 
keyword, and the copy is for a full volume (DFSMSdss COPY FULL command), the following 
will be honored based on whether FlashCopy is installed:

Note: Many of the benefits of using Concurrent Copy also apply to using FlashCopy, with 
the added benefits of not using host resources (channel bandwidth, memory). However 
you will need to allow for FlashCopy space in your disk subsystems. You will need to 
decide which technique offers the best return for your business requirements.