Latest Entries

Storage networking devices include processors (host servers), channel and host bus adapters (HBAs), switches (including directors), and storage devices (disk and tape, including virtual tape). Some additional storage networking devices include bridges, gateways, and routers, which were mentioned in the October/November 2003 z/Journal article, “Has Open Storage for zSeries Finally Arrived?”. Figure 1 shows a storage network with two separate fabrics (I/O paths) for redundancy (Path A and Path B) with servers attached to both. Figure 1 also shows servers that are single-attached only to Path B. Servers are attached to switching devices (director or switch) that have storage attached to them. Figure 1 also shows a switching device connected to another switch on the right using interswitch links (ISLs) in what is known as a cascade topology. This is an example of a metropolitan area network (MAN) or wide area network (WAN) for remote storage access and mirroring for data protection and access…

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Exploiting CMS & CP in z/Linux

As we’ve seen in previous articles, Linux on the mainframe is largely similar to Linux on a PC. However, the main thrust of this ongoing series has been to show how Linux guests in a z/VM environment can leverage VM’s capabilities to do things otherwise impossible on a stand-alone Intel server. In this article, we’ll examine the use of CMS as an extremely smart BIOS for the z/Linux guest and how to maximize CP services and the CMS file system from within Linux itself.

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LINUX For zSeries: Expectations vs. Reality

It has been four years since IBM Distinguished Engineer Dr. Karl-Heinz Strassemeyer talked at length about running Linux on the mainframe at the World Alliance of VM and VSE (WAVV) Conference in Fort Mitchell, KY. Linux on the mainframe has come a long way since then. There were—and still are—many high expectations of the platform, which have been tempered somewhat by a big dose of reality in the form of deployment successes and failures. It is easy to talk about the successes, which range from the miniscule to the downright glorious. However, it isn’t as easy to talk about the failures, which at times threaten to cast a pall on the platform and spawn fear and doubt for the new Linux on zSeries technology…

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zHoliday Storage Spirit

From FICON to fabric and “virtualization” to the many “natural” and manmade events that show disaster recovery in action, what a year it has been! Now that the holidays are upon us, I thought it would be a good time to reflect on the year gone by and present my wish list and predictions for the year ahead. So, what’s on your wish list this year? More storage, disk, or tape? There’s connectivity and interfaces for FICON and more switch and director ports. How about we dust off last year’s plan and finally put in that SAN? What about LANs, MANs, WANs, SANs, POTs (pretty old technology) and PANs (pretty amazing new stuff)? Is this real or part of the “virtual” storage land?…

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Using RACF To Control Access To DB2 Objects

Ever since the release of DB2 Version 5 and OS/390 Version 2, Release 4, you have had a choice of how you protect your DB2 resources: native DB2 controls or RACF. An effective DB2 security implementation using RACF requires close coordination between your DBA team and your security implementation (RACF) team. This article describes the security mechanisms available with RACF…

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The Event-Driven Enterprise

Organizations trying to become an agile, real-time enterprise often don’t notice that most of their critical business events lie dormant, locked within the safe confines of their complex operating systems. Event-driven architecture offers the promise of unlocking business potential in a world where business processes and their dependencies on business events occur without latency. Imagine a corporation where:…

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Are your OS/390 applications experiencing virtual storage constraints? If you don’t know and don’t know how you can find out, then this article is for you. Some applications, such as DB2, use a tremendous amount of “above the line” virtual storage. If the virtual storage consumption is not monitored, you could unexpectedly experience virtual storage constraints, leading to application failures. Monitoring virtual storage consumption is one step you can take toward proactive capacity planning in your environment. This article will demonstrate how you can use IBM’s RMF product to monitor the virtual storage utilization of specific address spaces running on your system…

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