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HP NonStop Transaction Management Facility (TMF) software provides the foundation for data integrity on all HP NonStop server platforms. TMF offers a unique and complex two-phased commit process for every change to a NonStop database, ensuring that all parts of a transaction are completed before the final change is captured (committed), and allowing for safe back out, when needed.
Most current “active/active” architectures replicate TMF-protected transactions in an asynchronous, bidirectional manner, enabling two or more NonStop systems to process transactions to one database of record. Each system has an updated copy of the database of record. If one system should be unavailable, the other(s) carry the full load of processing with little, if any, disruption of service. However, one by-product of these designs is the frequent possibility of data “collisions,” when two systems update the same record at the same time – which update should be accepted? There are various schemes to reduce or almost eliminate these collisions, but none absolutely guarantees no loss of database integrity.
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TMF can now assist in safer active/active replication
With the long-awaited release of the HP NonStop TMF Synchronous Gateway, safe participation in the TMF transaction commit process now gives applications the opportunity to guarantee none of the expected “data collisions” that result in many active/active asynchronous replication architectures. This new product is purchased from HP but relies on the replication technology of our HP NonStop partners. In itself, this product is only part of a full solution, but it provides the critical enabling element. Partners design their software to use this gateway to become a “voting” member of the TMF commit process and thus control their participation and eliminate data collisions. One trade-off in this kind of solution may be system performance, but it depends on the application and the way the application is integrated in the process. Customers need to discuss their specific environment and requirements directly with HP replication software partners.
A new set of APIs
This product is a collection of Application Programmable Interfaces (APIs) related to “Open TMF“ library modules. It provides, among others, a key interface for the TMF Volatile Resource Manager function. Partners can modify their current replication products to use these interfaces to coordinate transaction commits and thus support synchronous active/active replication, avoiding data collisions.
The new APIs available provide safe, limited access to selected Open TMF libraries:
- OTMF_VOL_RM_OPEN_
- OTMF_EXPORT_
- OTMF_EXPORT_ASYNC_
- OTMF_WAIT_SIGNAL_
- OTMF_WRITE_SIGNAL_
- OTMF_INTERPRET_SIGNAL_
More information
HP NonStop TMF Synchronous Gateway is now available as an independent product for HP NonStop servers (SA48v1), HP Integrity servers (HSA48v1), and HP Integrity NonStop BladeSystems (QSA48v1).
Interested developers or customers may request more technical information about the product from their HP account team who will contact the product manager.
For more details on HP NonStop business continuity products, see www.hp.com/go/nonstopcontinuity
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