136 DS8000 Series: Concepts and Architecture
Figure 7-15 Consistency Group: Example.3
In this case, the copy created by the Consistency Group operation reflects only the 1st and
3rd write operation, not including the 2nd operation.
If you accept this result, you can use the Consistency Group operation with your applications.
But, if you cannot accept it, you should consider other procedures without Consistency Group
operation. For example, you could stop your applications for a slight interval for the backup
operations.
7.3 Interfaces for Copy Services
There are multiple interfaces for invoking Copy Services. We describe them in this section.
7.3.1 Storage Hardware Management Console (S-HMC)
Copy Services functions can be initiated over the following interfaces:
zSeries Host I/O Interface
DS Storage Manager web-based Interface
DS Command-Line Interface (DS CLI)
DS open application programming interface (DS Open API)
DS Storage Manager, DS CLI, and DS Open API commands are issued via the Ethernet
network, and these commands are invoked by the Storage Hardware Management Console
(S-HMC). When the S-HMC has the command requests, including those for Copy Services,
1st
2nd
3rd
independent
for each write
operation
Servers
Completed
Wait
LSS11
LSS12
LSS13
This write operation is
completed because
LSS11 is not in an
extended long busy
condition.
This write operation is
not completed
because LSS12 is in
an extended long
busy condition.
Completed
This write operation is
completed because LSS13
is not in an extended long
busy condition.
(I/O sequence is not kept.)
