Search

Top 60 Oracle Blogs

Recent comments

data guard

warning: Invalid argument supplied for foreach() in /www/oaktable/sites/all/modules/cck/content.module on line 1284.

n/a

Rolling upgrads using logical standby database.

Couple of weeks ago there was a Twitter discussion started by Martin Bach (@MartinDBA) about cases for logical standby implementation. A rolling upgrade was mentioned by Tim Gorman (@timothyjgormanas) as one of potential recommendations for using this rare use product. I have been involved in such project in the past and I prepared an instruction and did quite large number of rolling upgrades from 11.1 into 11.2.

There are couple of my “gotchas”

Rolling upgrads using logical standby database.

Couple of weeks ago there was a Twitter discussion started by Martin Bach (@MartinDBA) about cases for logical standby implementation. A rolling upgrade was mentioned by Tim Gorman (@timothyjgormanas) as one of potential recommendations for using this rare use product. I have been involved in such project in the past and I prepared an instruction and did quite large number of rolling upgrades from 11.1 into 11.2.

There are couple of my “gotchas”

Data Guard 12c New Features: Far Sync & Real-Time Cascade

UKOUG Oracle Scene has published my article about two exciting Data Guard 12c New Features:

http://viewer.zmags.com/publication/62b883ad#/62b883ad/44

Far Sync Instance enables Zero-Data-Loss across large distance

Hope you find it useful :-)

RAC 12c enhancements: adding an additional SCAN-part 4

This is going to be the last part of this series, however long it might end up being in the end. In the previous articles you read how to create a physical standby database from a RAC One database.

Networks (refresher)

To make it easier to follow without going back to the previous articles, here are the networks I’m using, listed for your convenience.

  • 192.168.100/24: Client network
  • 192.168.102/24: Dedicated Data Guard network

Data Guard Broker Configuration

RAC 12c enhancements: adding an additional SCAN-part 4

This is going to be the last part of this series, however long it might end up being in the end. In the previous articles you read how to create a physical standby database from a RAC One database.

Networks (refresher)

To make it easier to follow without going back to the previous articles, here are the networks I’m using, listed for your convenience.

  • 192.168.100/24: Client network
  • 192.168.102/24: Dedicated Data Guard network

Data Guard Broker Configuration

RAC 12c enhancements: adding an additional SCAN-part 3

Travel time can be writing time and while sitting in the departure lounge waiting for my flight I use the opportunity to add part 3 of the series. In the previous two parts you could read how to add a second SCAN and the necessary infrastructure to the cluster. Now it is time to create the standby database. It is assumed that a RAC One Node database has already been created on the primary cluster and is in archivelog mode.

Static Registration with the Listeners

The first step is to statically register the databases with their respective listeners. The example below is for the primary database first and standby next, it is equally applicable to the standby. The registration is needed during switchover operations when the broker restarts databases as needed. Without static registration you cannot connect to the database remotely while it is shut down.

RAC 12c enhancements: adding an additional SCAN-part 3

Travel time can be writing time and while sitting in the departure lounge waiting for my flight I use the opportunity to add part 3 of the series. In the previous two parts you could read how to add a second SCAN and the necessary infrastructure to the cluster. Now it is time to create the standby database. It is assumed that a RAC One Node database has already been created on the primary cluster and is in archivelog mode.

Static Registration with the Listeners

The first step is to statically register the databases with their respective listeners. The example below is for the primary database first and standby next, it is equally applicable to the standby. The registration is needed during switchover operations when the broker restarts databases as needed. Without static registration you cannot connect to the database remotely while it is shut down.

Active Data Guard – what does it mean?

There are misconceptions and half-truths about that term that I see time after time again in forums, postings and comments.

Some people think that Active Data Guard is a fancy marketing term for Standby Databases in Oracle. Wrong, that is just plain Data Guard :-)

Most people think that Active Data Guard means that a Physical Standby Database can be used for queries while it is still applying redo. Not the whole truth, because that is just one featureReal-Time Query – which is included in the Active Data Guard option.

Active Data Guard is an option, coming with an extra charge. Active is supposed to indicate that you can use the standby database for production usage – it is not just waiting for the primary database to fail.

In 11g, Active Data Guard includes three features:

Data Guard transport lag in OEM 12c

I have come across this phenomenon a couple of times now so I thought it was worth writing up.

Consider a scenario where you get an alert because your standby database has an apply lag. The alert is generated by OEM and when you log in and check-it has indeed an apply lag. Even worse, the apply lag increases with every refresh of the page! I tagged this as an 11.2 problem but it’s definitely not related to that version.

Here is a screenshot of this misery:

 Lag in OEM

Now there are of course a number of possible causes: