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  • 1.  DB2 Mirroring

    Posted Thu November 30, 2023 05:11 PM

    Planning for mirroring of one library created by DB2 (not a native IBMi library) - DB2LIB001.

    Requirements

    1a) Synchronous replication of DB2LIB001 in IBMi Server A (LPAR 2) to IBMi Server B (LPAR2) in the same data center [OR]

    1b) Synchronous replication of DB2LIB001 in IBMi Server A (LPAR 2) to a Linux Server DB2 in the same data center

    2) End of Day mirroring of DB2LIB001 in IBMi Server A (LPAR2) to a Linux/ Windows Server DB2 in a different location, thousands of miles away.

    Does IBMi DB2 mirroring support 1b and 2 requirements?



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    Solomon John Downy Nallathambi
    Regional Head of Digital, Technology and Cyber Risk
    HSBC
    Dubai
    +971501307373
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  • 2.  RE: DB2 Mirroring

    Posted Thu November 30, 2023 09:18 PM
    Edited by Satid Singkorapoom Thu November 30, 2023 10:13 PM

    Dear Solomon

    Assuming you are actually asking about Db2 Mirror for i product, the answer is that  Db2 Mirror for i doe NOT support scenario 1b and 2.  What you ask for in 1b and 2 falls into what should be called cross-platform data replication and there are data replication products in the market that can do this, but not Db2 Mirror for i as it is actually replicating in-memory data as opposed to replicating row changes at database management level.    IBM Infosphere Data Replication product is one candidate for your question.

    One last point, your statement ".... one library created by DB2 (not a native IBMi library) ..." is indicative of a misunderstanding.  When you create a schema, table, or view by Db2 for i SQL, all these entities also exist in IBM i "native" perspective as well (as library, physical file, logical file) because of the fact that Db2 for i is an "integrated" component of IBM i.   They are two sides of the same coin. :-) 

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    Chance favors only the prepared mind.
    -- Louis Pasteur
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    Satid S.
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    Original Message


  • 3.  RE: DB2 Mirroring

    Posted Mon December 04, 2023 09:32 AM

    If only one system is active at a time (master, slave), you can use "power ha" licensed product that runs natively in a IBMi partition. This copies data at "block level/disk level" without particular dependencies. If you for some reason want to strictly protect "just one library", just put such library in the protected ASP.

    It does support strict synchronous copy, this of course put pressure also on the source system (because of course ack to the write is given when data is on the copy system first). So plan accordingly (network latency and bandwidth, with stress on latency).

    And nowadays, PowerHA does supports also multi-targets, without involving external SAN/arrays.

    It is not clear to me exactly the buffering limit of the Asynchronous mode, it could and does have a backpressure on the primary in saturation cases, I just cannot find any reference about how big/tunable the internal queues are (say, to put the target on cloud, unreliable connections, downtimes...).

    The only doc I find on powerha are scarce in details, the only doc I've been able to find is https://www.ibm.com/support/pages/powerha-geographic-mirroring-asyncasync-explained

    Maybe the powerha team can chime in and explain the details...



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    --ft
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    Original Message


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