IBM DS6000 Series manual Command flow, ESS Copy Services command flow using ESS Copy Services CLI

and then follows the prompts. If using a GUI, the user navigates to the CD root directory and clicks on the relevant setup executable.

3.The DS CLI is then installed. The default install directory will be:

–/opt/ibm/dscli - for all forms of UNIX

–C:\Program Files\IBM\dscli - for all forms of Windows

–SYS:\dscli - for Novell Netware

10.5Command flow

To understand migration or co-existence considerations, it is important to understand the flow of commands in both the ESS CLI and the DS CLI.

ESS Copy Services command flow using ESS Copy Services CLI

When using the ESS Copy Services CLI with an ESS 800, all commands are issued to a Copy Services Server, present on one cluster of the ESS. Interaction with this server is via either a Web Copy Services GUI interface, or via a CLI interface. To use the CLI, the open systems host needs to have ESS Copy Services CLI software installed. An ESS CLI script will issue commands to the CLI software, which then sends them to the primary Copy Services Server (known as Server A). For backup, a second server can also be defined (known as Server B).

Figure 10-1 on page 199 shows the flow of commands from host to server. When the Copy Services (CS) server receives a command, it determines whether the volumes involved are owned by cluster 1 or cluster 2. This is based on LSS membership (even numbered LSSs belong to cluster 1, odd numbered LSSs belong to cluster 2). The CS server issues the command to the client software on the correct cluster and then reports success or failure back to the CLI software on the open systems host.

198DS6000 Series: Concepts and Architecture