IBM Data Replication's CDC News
DavidT 120000JC6D Tags:  db2 data_replication netezza oracle infosphere 2 Comments 6,278 Views
If you're looking for an excellent way to replicate changed data from a wide range of databases into a Netezza appliance, you can do so through InfoSphere Data Replication. The latest release provides an Apply program that is both native to Netezza and optimized for Netezza targets. This Apply is built from Data Replication's CDC technology and is also compatible with the CDC technology found in InfoSphere Change Data Capture and InfoSphere Classic Change Data Capture for z/OS. This means you can replicate data to Netezza from source databases ranging from Oracle, DB2, and others on UNIX or Windows to DB2* and IMS on the mainframe. Ordering information can be found in the Data Replication announcement letter on ibm.com.
* Data Replication's CDC Apply program cannot be used to feed changed data to the IBM DB2 Analytics Accelerator (IDAA).
For those of you who don't subscribe to the IBM Redbook newsletter, you may have missed last week's announcement of a new Redbook titled Implementing IBM InfoSphere Change Data Capture for DB2 z/OS V6.5. It is a exellent extension of the brief CDC z/OS sections found in last year's Redbook titled Co-locating Transactional and Data Warehouse Workloads on System z. This new Redbook provides information about installing, configuring, running, and tuning CDC for DB2 z/OS. Read it if you need it and don't forget to rate it (no one will cry if you give it 5 stars :)
With the announcement of InfoSphere Data Replication 10.1.2, IBM added a product called InfoSphere Data Replication for Database Migration. This new product is a tool to help you with hardware and database upgrades. It is intended for short-term use. For example, if you're upgrading to a totally new hardware platform, the new Data Replication product keeps two copies of your database in sync - one copy on your old hardware and the other on your new hardware. This gives you the time you need - a few weeks or several months - to migrate and test applications before you turn off the old hardware. A similar scenario is possible if you're just upgrading databases or if you're upgrading hardware and databases simultaneously.
The first release of the new product is available for three different combinations of source and target databases (three different from and to combinations):
It provides only the data replication function needed for database migration. Specifically:
Note that there are two licensing differences for this Data Replication product when compared to many other products. First, this one is licensed by target server install instead of a PVU (processor value unit) count. That means for each target install you license, you can install at a single source for no additional charge. Second, IBM does not offer a non-production version. Therefore, you buy the same product for both production and non-production uses. This isn't bad since this database migration product is significantly cheaper than the full Data Replication product. To verify these licensing points and others, always see the the license file on ibm.com as the official word in how licensing works.
If you have questions, feel free to post them to the message board.
This post is the answer to one of the FAQs found in
This post is the answer to one of the FAQs found in Licensing Tips for IBM Data Replication.
In April 2013, IBM announced Version 10.5 of DB2 for Linux, UNIX, and Windows. The same letter announced that DB2 AESE and DB2 AWSE would provide limited use of IBM InfoSphere Data Replication's (IIDR's) Change Data Capture (CDC) technology at no additional cost. However, the "limited use" statement sometimes leaves people with a question or two. The goal of this post is to answer those questions.
First, what CDC function are you entitled to use in the DB2 Advanced Editions? The license is the always final word, but, in simple terms, you can only use the bundled CDC to build disaster recovery solutions where a primary DB2 instance* has up-to-two backup instances. For example, the following replication topology is allowed by the DB2 Advanced Edition licenses:
Furthermore, the disaster recovery use case limits your entitled use of CDC function in the following ways:
The question is - when do you need to buy CDC now? If you want to do anything more than what's described in this post, you'll need to buy IIDR for your DB2 Advanced Editions. The two most common replication configurations that require this are ones where you do either of the following:
If you need to understand more about these examples, we'll have pictures and add a few more examples in a future post that talks about when you need to buy CDC.
Of course, the last question is - can I still build DB2 DR, HA, and Active-Active solutions using the Q Replication built into the DB2 Advanced Editions? Yes, absolutely. The addition of CDC to DB2 does not change this.
* Multiple DB2 instances can be created from a single DB2 install. Each instance can use the bundled CDC to replicate up to the entitled number of backup instances.
Now that IBM has packaged its major data replication technologies into a single product, InfoSphere Data Replication, a lot of people are asking what they can take advantage of that they couldn't with the older products (InfoSphere CDC and InfoSphere Replication Server). Other than the obvious point of having access to multiple technologies, you can now use IBM's table compare utility, asntdiff, with CDC. asntdiff is a general-purpose utility that compares the data from two queries. IBM provides it through several product - Replication Server, the IBM Data Server Client, and all editions of DB2 and InfoSphere Warehouse.*
Long-time CDC users may ask what's happening to CDC's differential refresh and why they would want to use asntdiff instead of differential refresh. First understand that differential refresh is alive and well and it's not going anywhere :) asntdiff is just an option available to you.
To understand when you might want to use asntdiff, understand the basics of how it works.
So, the first reason to consider asntdiff is times when differential refresh's restrictions could be overcome by writing queries to get the result sets you need. For example, asntdiff may be an alternative if one of the following differential refresh restrictions applies to your replication configuration:
Next, asntdiff is independent of data replication and can be started from a command line. Among other things, this means:
One major point to be aware of with asntdiff is how it works with heterogeneous data. For example, when you want to compare data being replicated from Oracle to DB2. asntdiff was originally written for DB2 databases. As a result, it requires IBM data federation technology to query databases such as Oracle. The good news is that InfoSphere Data Replication provides data federation for use with data replication configurations.
If you're not familiar with asntdiff and want to give it a try, see the ChannelDB2.com blog post titled Compare the Rows of Two Tables. If you have questions, feel free to post them in the CDC message board here on developerWorks.
* Yes, technically, you could already use asntdiff with CDC on UNIX or Window since it comes in so many IBM products on UNIX and Windows. However, if you wanted to use it on z/OS, you could only get it through Replication Server. It's now in InfoSphere Data Replication as well.
With a mere 4 weeks until IBM's 2013 Information on Demand, the data replication team thought it might be helpful to have a complete listing of all data replication sessions at IOD. From client presentations and our product roadmap to sneak peeks at new IBM Data Replication functionality, our sessions run the gamut!
Simply take a gander at the sessions below then go to the IOD agenda builder, click on Create Sign In, and then enter your confirmation number and the email address that you used to register for the conference. Create your agenda today!
Tuesday, Nov 5