NO! You don't want to duplex the LOCK and SCA structures.
We don't do it.
IBM explicitly recommends not to do it under Planning for availability.
Configure a simplexed SCA and lock structure in failure-isolated
coupling facilities. (When duplexed, the SCA and lock structure do not
need to be in failure-isolated coupling facilities.)
Duplexing the SCA and lock structure offers marginally faster recovery
times compared to dynamically rebuilding a simplexed SCA and lock
structure. Duplexing also enables you to use internal coupling
facilities (ICFs), which provide cost savings over stand-alone coupling
facilities without compromising availability. However, before you decide
to duplex the SCA and lock structure, you should consider that:
Duplexing the SCA and lock structure does not add significant
availability, because the structures can be rebuilt very quickly from
in-memory data.
Duplexing the SCA and lock structure can cause a significant impact on
performance. In most cases, the overhead that is incurred by duplexing
these structures outweighs the availability benefits of duplexing.
The IGS Performance team related that they have found other customers
doing this and the overhead was very high.
Best Regards,
Sam Knutson, GEICO
System z Performance and Availability Management
mailto:[EMAIL PROTECTED]
(office) 301.986.3574
"Think big, act bold, start simple, grow fast..."
-----Original Message-----
From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On
Behalf Of Pawel Leszczynski
Sent: Tuesday, December 11, 2007 11:21 AM
To: [email protected]
Subject: db2 lock structures duplexing
Hello everybody,
I've got a question to guys running DB2 in parallel sysplex environment.
Do you duplex DB2 lock structures i.e. _LOCK and _SCA structure?
What is the overhead connected with it?
In our 2-node PS environment we don't have stand-alnone CF, only
internal CF in two different footprints.
We want to avoid situation when damage of one of the boxes
will bring the whole DB2 sharing group down.
Regards,
Pawel Leszczynski
PKO BP SA
====================
This email/fax message is for the sole use of the intended
recipient(s) and may contain confidential and privileged information.
Any unauthorized review, use, disclosure or distribution of this
email/fax is prohibited. If you are not the intended recipient, please
destroy all paper and electronic copies of the original message.
----------------------------------------------------------------------
For IBM-MAIN subscribe / signoff / archive access instructions,
send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO
Search the archives at http://bama.ua.edu/archives/ibm-main.html
