There is not enough information in your question for a reasonable answer, IMHO. Missing, for example, is the number of LPARs and how the 'plex is configured. Also missing is the specific DASD hardware as well as competing workloads (other datasets on that same unit and the cache hit rate on that specific extent of that volume). Even with that information, the equations are complex.
One or more very high performance jobs (ADRDSU, for example) on an LPAR can dominate the unit and degrade performance to the perception of 'stopped'. The SWAG ROT is that there is no free lunch, and each additional job will degrade performance to some degree. The first few may not be measurable. The degradation may follow a classic 'knee curve' (rise slowly to a point then abruptly get much worse). Degradation to the point of a perceived job *stoppage* is not likely. Degradation to a point of unacceptable run times is the expected result. HTH and good luck. -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Chase, John Sent: Monday, May 01, 2006 8:46 AM To: [email protected] Subject: Dataset Contention Hi, All, The following question was posed in our shop recently: "How many jobs can access a DISK DSN with a DISP=SHR before any performance degradation occurs due to access contention? "Meaning, We have 1 dataset sitting on disk, we have 35 jobs that need to access this one dataset, how many jobs can run at one time accessing this one dataset before the access creates contention and stops jobs from running?" All of the access would be read-only, and AFAIK the dataset is non-VSAM. TIA, ---------------------------------------------------------------------- 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
