SMB (System Managed Buffering) is one of the better Performance options to apply to VSAM datasets in a long time and should be considered.
In order for a VSAM dataset to be suitable for SMB is must be SMS managed and defined to SMS in the appropriate Data Class as an Extended Format Data Set (DATASETNAMETYPE=EXT). SMB should always be used for REPRO's and depending on the definition in the Cluster will use CO (Create Optimized) if the Cluster is defined with SPEED or CR (Create Recovery Optimized) if the Cluster is defined with RECOVERY. Both options are not declared in the ACCBIAS, VSAM uses them only for Repro. The other options are : DO (Direct Optimized) DW (Direct Weight) SO (Sequential Optimized) SW (Sequential Weight) VSAM will use the above options if Specified in the ACCBIAS..AMP JCL statement, and the activity on the dataset matches the option specified. For example, for DO, the buffers allocated will suit the access if it is mostly, if not all, Random access, so more Index buffers will be allocated. HTH Colin Pearce -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Yifat Oren Sent: Monday, June 17, 2013 10:04 PM To: [email protected] Subject: Re: Question about LSR vs HiperBatch It may be worth noting that HiperBatch only caches the data component of a VSAM cluster indeed making it quite useless for direct/random access. DFSMS SMB makes LSR in batch real easy to use - but it is a Local Shared Resource; in case many users need to access/update the VSAM cluster at the same time - RLS may be another option to consider. Best Regards, Yifat Oren -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Farley, Peter x23353 Sent: Monday, June 17, 2013 4:39 PM To: [email protected] Subject: Re: Question about LSR vs HiperBatch Hiperbatch is limited to 2GB of data for all files cached across the entire sysplex. It is a "stabilized" product no longer being actively updated. We use it for one particular file used across many applications, but that is the only file we can use it for since it is a large file (> 1.5GB). Also Hiperbatch works well for sequential access, but random access does not seem to benefit as much. Batch LSR works very well for random access (we use it quite a lot), but you may instead want to investigate the much newer System-Managed Buffering (SMB) capability, documented in the JCL reference and user guide manuals (cf. DD parameter AMP, sub-parameter ACCBIAS et. al.). HTH Peter -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Mowry, Norma E CIV DISA ESB (US) Sent: Monday, June 17, 2013 8:04 AM To: [email protected] Subject: Question about LSR vs HiperBatch We are looking into using either Batch LSR (local shared resources) or HiperBatch for batch jobs that use the same resources (VSAM files...) What (if any) are the recommendations, pitfalls of each or is the another option to do this? We are running z/OS V1.13. Thanks Norma Mowry DECC-Mechanicsburg Operating Systems Support (ESB11) (717)-605-7865 DSN:430 e-mail address: [email protected] ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN This message and any attachments are intended only for the use of the addressee and may contain information that is privileged and confidential. If the reader of the message is not the intended recipient or an authorized representative of the intended recipient, you are hereby notified that any dissemination of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by e-mail and delete the message and any attachments from your system. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- This message, and any attachments, is for the intended recipient(s) only, may contain information that is privileged, confidential and/or proprietary and subject to important terms and conditions available at http://www.bankofamerica.com/emaildisclaimer. If you are not the intended recipient, please delete this message. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
