New to IBM PureData System for Transactions: DB2 10.5 and HADR

KellySchlamb

Kelly Schlamb, DB2 pureScale and PureData Systems Specialist, IBM

In a comment on my previous blog post, somebody recently asked about when the PureData System for Transactions was going to be updated to include DB2 10.5, the latest and greatest version of DB2 that was released on June 14th, 2013.  At the time, I hinted that it would be coming soon but I couldn’t share any details.  The curtain can now been lifted.

PureData System for Transactions Fix pack 3 was made available for download on July 31st (and any new deployments of the system will automatically have this level as well).  This fix pack adds DB2 10.5 to the software stack of the system.  So, when you go to deploy a cluster you can now choose to deploy either DB2 10.1 or 10.5, depending on your needs.

As with every major release of DB2, this new version is jam-packed with countless features and enhancements.  There’s a lot of great information out there about 10.5 if you’re interested in reading more, including some entries from fellow blogger, Bill Cole and the What’s New section in the Information Center.

While many things will be of general interest to people – such as performance enhancements, new SQL capabilities, and further Oracle compatibility updates – I did want to specifically call out something that will be of great interest to those interested in the DB2 pureScale feature and PureData System for Transactions (which has pureScale built into it).  This is the addition of HADR support.  HADR is DB2’s High Availability / Disaster Recovery feature.  With HADR, changes to a primary database are replicated via transaction log shipping to one or more standbys, allowing for both local high availability and longer distance disaster recovery.  There are many reasons why DB2 users have embraced HADR, but the one I hear all the time is that it’s built right into DB2 which makes it very easy to setup and maintain.

In the case of a pureScale environment, you’re already getting the highest levels of availability.  For instance, with pureScale in the PureData System for Transactions box, a compute node failure wouldn’t result in the database going offline.  In this case, other compute nodes associated with the cluster would still be available to process database transactions.  So, with HA already being accounted for, the value in using HADR in this type of environment is for setting up a disaster recovery system.  Now, you do have other options for disaster recovery of PureData System for Transactions, such as using QReplication, and there is functionality within QRep that might make it a more suitable choice for a particular database (such as only having a need to replicate a partial set of the data in the database).  But with HADR you have another option and those that use it and love it today for their traditional DB2 environments, can now use it here as well.  For example, you can have a PureData System for Transactions at your primary site and another one at your disaster recovery site.  HADR is enabled at the database level and for one or more databases on the primary system, you can create a standby version at the other site.  If there is ever a need to failover to that standby site, it’s a relatively simple process to perform the takeover of the databases on the standby.

Rather than getting into the specifics about how this works, how to configure the environment, etc. I’m going to take the easy route and point you to this comprehensive document on this topic.

Just learning about the product? Check out the PureData for Transactions page .

5 Responses to New to IBM PureData System for Transactions: DB2 10.5 and HADR

  1. Kelly,

    thanks for the great article. Is it possible the ship the logs to a single database not to a pureScale cluster? It would be enough for us in a desaster scenario.

    Regards,
    Joachim

    • Kelly says:

      Hi Joachim. The target/DR system must be another cluster with a matching member topology (i.e. same number of members). With PureData System for Transactions, the cluster sizes you choose from and the resources associated with each are predefined, and so you’d be going from a cluster on the primary to a matching cluster on the standby system. If you just want a non-pureScale database as the standby you do have the option of using IBM’s QReplication or CDC replication technology instead. This functionality is already included in the licensing for the PureData box when used for DR purposes.

      Going back to HADR for a second, If you’re using pureScale in your own “home built” system then the HADR standby cluster has to have a matching topology but you can associate less resources (CPU, memory) with each of the members and CFs on it — if you don’t need the same kind of horsepower. Also, in this type of situation you can consider having the members on the standby share a host (so same number of members, but less hosts/servers/LPARs to manage).

      Kelly

  2. marcoita says:

    Thanks for this nice article!

    There is also a whitepaper about HADR in PureData for transactions:

    http://www.ibm.com/developerworks/data/library/techarticle/dm-1308puredatarecovery/

  3. Rodrigo says:

    Hi Kelly, congrats for the article. I have a primary cluster with 4 LPARs with members (2) and CFs (2) separately. Can I built a valid HADR target/DR cluster with just 2 LPARs (one member and one CF together in each LPAR) ?

  4. Kelly says:

    Thanks Rodrigo. I assume that you’re asking about a customized pureScale cluster on Power/AIX here (and not a PureData System for Transactions). We do allow flexibility in how the CFs and members are defined when talking about the target/DR cluster, including being able to have things collocated within LPARs. We’ve got some information about this kind of thing here: http://pic.dhe.ibm.com/infocenter/db2luw/v10r5/index.jsp?topic=/com.ibm.db2.luw.admin.ha.doc/doc/c0061085.html. If you have any additional questions, please feel free to reach out to me on LinkedIn and send me a note. Also, it sounds like you’re using pureScale today and so I’d like to hear more about your experiences.

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