SVA - Virtual Disk Storage in a Sysplex Environment

Asset ID:	1-71-1013097.1
Update Date:	2011-05-31
Keywords:

Solution Type Technical Instruction Sure

Solution 1013097.1 : SVA - Virtual Disk Storage in a Sysplex Environment

Applies to:

Sun StorageTek V2X SVA Disk System - Version: Not Applicable to Not Applicable - Release: N/A to N/A
All Platforms

Goal

Some cases have shown that alternate sysplex data sets have not been allocated or the primary and alternate sysplex data sets have been allocated on the same disk subsystem.

Solution

To avoid a single point of failure in the sysplex, IBM recommends that, for all couple data sets, you create an alternate couple data set on a different device, control unit, and channel from the primary.

Information about the sysplex and the services that use couple data sets is maintained in both the primary and alternate couple data sets concurrently. If the primary data set fails, the sysplex automatically makes the alternate the primary.

Installing Microcode Non-disruptively in Sysplex Environments

1. In SYSPLEX environments, the control unit busy sequence created by the concurrent microcode activation may create error messages with the COUPLE Data Sets in the XCFAS address space. Customers in these environments should be aware of this possibility and be prepared to take appropriate recovery actions.

2. Request the customer to verify that primary and alternate couple data sets are operational and not on the same physical subsystem that is to receive the microcode activation.

Issue this MVS display command: D XCF,COUPLE,TYPE=ALL

3. To deallocate the primary couple data set and dynamically switch the alternate to the primary, issue this MVS control command: SETXCF COUPLE,PSWITCH

4. To assign a formatted spare couple data set to be the new alternate, issue this MVS control command: SETXCF COUPLE,ACOUPLE=(alt-dsname,alt-volume), TYPE=dstype

5. After the microcode activation is complete, the customer may choose to switch the primary and alternate couple data sets.

IBM Manual References

MVS System Commands

Setting Up a Sysplex

kdw 2/12/2002 created

Previously Published As
91069

Change History
Date: 2007-10-08

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