September 20, 2012

IprediaOS automatically encrypts network traffic using the I2P network


IprediaOS is a fast, powerful and stable operating system based on Linux that provides an anonymous environment. Many applications are available in IprediaOS, including mail, peer-peer, bittorrent, IRC chat and others.

All network traffic is automatically and transparently encrypted and anonymized using the I2P network.

With IprediaOS you get

  • I2P Router
  • Anonymous BitTorrent client
  • Anonymous e-mail client
  • Anonymous IRC client
  • Browse Internet anonymously
  • Find anonymous eepSites (i2p sites)

About the I2P Project

I2P is an anonymizing network, offering a simple layer that identity-sensitive applications can use to securely communicate. All data is wrapped with several layers of encryption, and the network is both distributed and dynamic, with no trusted parties.

Run IprediaOS as a virtual machine with VirtualBox

If you want to run IprediaOS as a virtual machine, it's quite possible to do so. Just select Linux and Fedora as the OS type and give the machine at least 768 MB memory.


Minimize the time it takes to enable referential constraints by doing it in parallel

Alter session to "FORCE PARALLEL DDL"

The table in this example is created with the NOPARALLEL attribute. Using ALTER SESSION FORCE PARALLEL DDL, the validation of the constraint is done in parallel. This cuts the time consumed to under one minute in my environment.

-- Disable the constraint (only takes a second)

-- Enable constraint in parallel takes about 40 seconds (NOPARALLEL takes approx. 5 minutes)

What the documentation says about ALTER SESSION ... PARALLEL

The PARALLEL parameter determines whether all subsequent DML, DDL, or query statements in the session will be considered for parallel execution. This clause enables you to override the degree of parallelism of tables during the current session without changing the tables themselves.

FORCE forces parallel execution of subsequent statements in the session. If no parallel clause or hint is specified, then a default degree of parallelism is used. This clause overrides any parallel_clause specified in subsequent statements in the session but is overridden by a parallel hint.

Specify ENABLE to execute subsequent statements in the session in parallel. This is the default for DDL and query statements.
  • DML: DML statements are executed in parallel mode if a parallel hint or a parallel clause is specified.
  • DDL: DDL statements are executed in parallel mode if a parallel clause is specified.
  • QUERY: Queries are executed in parallel mode if a parallel hint or a parallel clause is specified.

Read more about ALTER SESSION [ENABLE | DISABLE | FORCE] PARALLEL [DML | DDL | QUERY] in the Oracle documentation on the links below.

September 19, 2012

Unregister Oracle database from recovery catalog when db is unavailable

The normal RMAN method with database target connection

To unregister an Oracle database from a recovery catalog you normally connect to the target database and the recovery catalog using RMAN (recovery manager) and issue the UNREGISTER DATABASE command. Like this.

$ rman 
RMAN> connect target / 
RMAN> connect catalog rcat@rcatdb
RMAN> unregister database;

But what if you want to unregister a database that has been deleted, or is unavailable for other reasons?

September 1, 2012

Solution to CrashPlan restore showing "no files found"

Trying to restore a file from CashPlan backup, but your client application does not display any files or the message "no files found"? Before you panic, see if this solves your problem!

If you know that files have been previously backed up, it may indicate a problem with your local CrashPlan cache. This is just a display issue and is normally resolved by clearing the cache and have CrashPlan rebuild it. This operation does not affect your backed up data, it is simply re-scanning each file.

Here's how to do it...