Oracle and Microsoft to Interconnect Oracle Cloud and Microsoft Azure

On the 5th of June 2019, both Oracle and Microsoft made a joint announcement on the interconnection between Oracle Cloud and Microsoft Azure:

Oracle’s Press Release
Microsoft Press Release

The key aspects of the announcement are:

  1. A direct interconnect between Oracle Cloud and Azure Cloud, starting in Ashburn (North America) and Azure US East, with plans to expand additional regions in the future.
  2. Unified identity and access management, via a unified single sign-on experience (more...)

Online Redo Log Switch Frequency Map

A query I find myself often running is the online redo log switch frequency map query, which queries the v$log_history/gv$log_history (for cluster databases) view and show the historical log switch frequency.

Why you might ask? Well it’s important to see how frequent log switches are occurring as Oracle’s rule of thumb is to not switch more then 3 logs per hour (20 minutes of redo) at peak DML activity to prevent excessive checkpoints.  The (more...)

Prevent crontab jobs overlapping using flock

As an Oracle DBA, you may find yourself in the situation where you have crontab jobs overlapping.

For example an RMAN backup takes longer then normal, then overlaps with another RMAN database backup leading to more resources being consumed:

00 00 * * * /home/oracle/scripts/backups/db_backup.sh PROD1 >> /home/oracle/backups/logs/db_backup_PROD1.log 2>&1
00 01 * * * /home/oracle/scripts/backups/db_backup.sh PROD2 >> /home/oracle/backups/logs/db_backup_PROD2.log 2>&1

If the PROD1 backup takes longer then 1 hour, then it will (more...)

RMAN Incremental Updating Backup & Demo Part 1

This blog post is part of the “RMAN Back to Basics” series, which can be found here.

Incremental Updating Backup

An incremental updating backup is a level 0 incremental backup which is recovered using level 1 incremental backups.  This avoids the overhead of taking level 0 incremental backups, for example in a backup strategy where a level 0 is taken every Sunday and all other days level 1.

An simple example would be, an (more...)

VT-x is not available (VERR_VMX_NO_VMX) on VirtualBox after Windows 10 Update

So in the mist of writing my “RMAN Back to Basics” series, I got the following error when trying to start my Virtual Machine in Oracle’s VirtualBox:
VirtualBox_VERR_VMX_NO_VMX

“Failed to open a session for the virtual machine dc1sbxdb001

VT-x is not available (VERR_VMX_NO_VMX).
Result Code: E_FAIL (0x80004005)
Component: ConsoleWrap
Interface: IConsole {872da645-4a9b-1727-bee2-5585105b9eed}”

I was like, “How’s this possible?  I only just used my Virtual Machines yesterday!“.

Then I remembered Windows 10 (more...)

RMAN Incremental Differential vs Cumulative & Demo

This blog post is part of the “RMAN Back to Basics” series, which can be found here.

Differential Incremental Backups (default)

A differential incremental backup, backs up all the blocks that have changed after the most recent incremental backup, which can be either level 1 or 0.

RMAN determines which is the most recent level 1 backup and then backs up all the blocks changed after that backup, if no level 1 then all the (more...)

RMAN Incremental with Block Change Tracking & Demo

This blog post is part of the “RMAN Back to Basics” series, which can be found here.

Block Change Tracking

Block change tracking (BCT) improves incremental backup performance by recording the changed blocks in each datafile in the block change tracking file, thus avoiding the need to scan every block in the datafile for changes.  Only applicable for level 1 backups.  Block change tracking file is 1/30,000 the size of the data blocks being tracked, (more...)

RMAN Incremental & Demo Part 2 (Level 1)

This blog post is part of the “RMAN Back to Basics” series, which can be found here.

Incremental Backup

An incremental backup only backup up those data blocks that have changed since the last backup.

Types of Incremental Backups

There are 2 types of Incremental Backups:

  1. Level 0 are a base for subsequent backups.  Copies all blocks containing data similar to a full backup, with the only difference that full backups are never included (more...)

RMAN Incremental & Demo Part 1 (Level 0)

This blog post is part of the “RMAN Back to Basics” series, which can be found here.

Incremental Backup

An incremental backup only backup up those data blocks that have changed since the last backup.

Types of Incremental Backups

There are 2 types of Incremental Backups:

  1. Level 0 are a base for subsequent backups.  Copies all blocks containing data similar to a full backup, with the only difference that full backups are never included (more...)

RMAN Image Copy & Demo

This blog post is part of the “RMAN Back to Basics” series, which can be found here.

Image Copy

An Image copy backup are exact copies of the datafiles including the free space.  They are not stored in RMAN backup pieces but as actual datafiles, therefore are a bit-for-bit copy.

Image Copy Demo

We take an image copy backup using my script 4_image_copy.sh:

[oracle@dc1sbxdb001 demo]$ ./4_image_copy.sh 
-----------------------
Step 1: Set environment
 (more...)