What is HALDB? & RESLIB and What is RECON

psubra001 · New User Joined: 01 Feb 2006 Posts: 15

I'm an IMS application programmer. I got the following mail from DBA. Can somebody help me understanding this?

"IMT3(ims region)-GNCDUPDB(database) is now a HALDB. Please remember to use the right RESLIB. For example, if you are running on IMT3, please make sure you are using TIMS.IMT3.RESLIB. HALDB database does not use dynamic alloction library. HALDB uses information in RECON and dynamic allocates HALDB datasets"

I'm trying to understand the following. Could you please help?
- What is HALDB?
- What is RESLIB?
- What is dynamic alloaction?
- What is RECON?

IQofaGerbil · Posted: Tue Mar 13, 2007 5:10 pm

High Availability Large Database (HALDB) capability available with IMS. IMS HALDB was introduced with IMS Version 7. It allows IMS databases to grow to almost unlimited sizes while providing increased availability

RECON ,
VSAM files that hold information for DBRC
DBRC becomes mandatory for HALDB databases which also enforces the use of log datasets for update steps. DBRC uses a set of 3 Recon datasets to hold information about databases and their states. The dataset names of the databases are held in these Recon datasets and are used to dynamically allocate them when required so there is no need to code them explicitly in the JCL.

Dynamic allocation - system will allocate the dataset names for your databases without you having to code the DDnames in your JCL

RESLIB - for non-HALDB this is where the relationship between database name and related dataset name is held

plachira · New User Joined: 13 Mar 2007 Posts: 1 Location: Kerala

Hi IQofaGerbil,

Thank you for your explaination about HALDB. I have some queries.

How to code JCL for HALDB?
Should we need to specify RECON in our JCL for accessing this DB?

Thanks,
Plachira