SSR Correction
In our blog post on November 6 (http://watsonwalker.com/two-red-alerts/) and our Tuning Letter 2015 No. 3, we incorrectly specified the default status of SSR as disabled. The default is actually for it to be enabled if the associated Space Constraint Relief data class function is enabled. We’ve corrected the blog entry, but you may need to refresh the page to see the correction. Thanks so much to Greg Saccomanno from Wells Fargo for pointing that out, and to Terri Menendez for helping us understand the relationship to the data class attributes.
New Red Alert
Most installations hopefully have at least one person who subscribes to Red Alerts, but we think it’s important for more people to be aware of these. You can subscribe yourself at https://www14.software.ibm.com/webapp/set2/sas/f/redAlerts/home.html.
IBM has just issued Red Alert 2016.11.22 – IMS V12, V13 or V14 – potential for IMS to write incorrect log data and/or over-write 64-bit (key 7) common storage which might belong to another address space.
The users affected by this Red Alert are those running IMS V12 or later,
- Who are using log buffers in above-the-bar storage (BUFSTOR=64), or
- Have callers who supply an above-the-bar log record to the IMS Logger, such as:
- IMS 64-bit Fast Path buffer manager
- Installation-written or vendor-written software
Description:
The IMOVE macro (used by the IMS Logger) uses 32-bit instructions to advance the addresses of the source and target destinations. If the address being advanced is a 64-bit address which crosses a 4GB boundary, then the updated address is incorrect since only the low-half of the address is updated. The two areas of IMS that are exposed to this are the IMS Logger and the 64-bit Fast Path buffer manager. An IMS cold start across the sysplex might be required. For more information, click on the link above.
New Function APARs
You know how much emphasis we place on New Function APARs, especially now that Continuous Delivery is in full force. Because the default setting of most New Function APARs is for them to be disabled, you won’t get the benefits and enhancements unless you know about the APARs and can activate them. That’s why we’re very excited about a new IBM external web page for z/OS New Function APARs. Visit the recently-announced New Function APARs website at http://www-03.ibm.com/systems/z/os/zos/installation/zosnfapars.html. This is a really excellent site – it lets you see the last 12 months or last 5 years of New Function APARs in html format, or you can download the information in csv format and then sort it on component ID, component name, close date, APAR number, or any of a number of other fields. Marna Walle, Jeff Bland, and their colleagues in IBM really put a lot of time and effort into creating a site that provides the required information in as usable a format as possible.
CMG Spark Presentation
If you read our most recent Tuning Letter (2016 No. 3), you will have seen that we are very enthusiastic about the new IBM z/OS Platform for Apache Spark. That’s quite a mouthful, but it is quite a product. That article was just the first in a series of articles about our experiences with Spark.
At the recent CMG conference in La Jolla, Frank presented a session about Spark and SMF, and our experiences with getting it up and running. The initial feedback was very positive, with one customer stopping at the end of the session to say that he had changed his mind about Spark, and was going to see about installing it when he returned home. We have also been hearing of more and more companies that are lining up to perform Proof of Concepts with it.
As we said to a customer recently, if you can provide the same user interface on z/OS as on other platforms, and can run the analytics on z/OS in a cost-effective manner, and the data being analyzed originates on z/OS, how does it make sense to move all the data to another platform for analysis, especially if the result is going to be sent back to z/OS? We don’t believe that all your analytics should be run on z/OS, but we do believe that it makes sense to perform the analytics where the data resides. Particularly if your future plans include in-transaction analytics using z/OS operational data, we just don’t see how performing the analytics on any other platform makes sense.
If you would like to know a little more about our experiences with Spark on z/OS, download Frank’s slides here and tune in for the next installment in the series in the next issue of the Tuning Letter at the end of January. And if you are already working with Spark on z/OS, please share your experiences with us. We would love to know how other users are getting on.