Configure NTP on AIX 7.1 for Oracle RAC

Posted by on May 16, 2012 No comments
  1. Verify that you have a server suitable for synchronization. Enter:
  1. # ntpdate -d ip.address.of.server

    The offset must be less than 1000 seconds for xntpd to synch. If the offset is greater than 1000 seconds, change the time manually on the client and run the ntpdate -d again.

    If you get the message, "no server suitable for synchronization found", verify xntpd is running on the server (see above) and that no firewalls are blocking port 123.

  2. Specify your xntp server in /etc/ntp.conf, enter:
  1. # vi /etc/ntp.conf

    (Comment out the “broadcastclient” line and add server ip.address.of.server prefer.)Leave the driftfile and tracefile at their defaults.

  2. Start the xntpd daemon:
  1. # startsrc -s xntpd

    (Use the -x flag if it is appropriate for your environment.)

  1. Uncomment xntpd from /etc/rc.tcpip so it will start on a reboot.
  1. # vi /etc/rc.tcpip

    Uncomment the following line:

    start /usr/sbin/xntpd "$src_running" "-x"

    NOTE: Use the -x flag to prevent the clock from changing in a negative direction.

  2. Verify that the client is synched.
  1. # lssrc -ls xntpd

    NOTE: Sys peer should display the IP address or name of your xntp server. This process may take up to 6 minutes.

in IBM Support

ATENTION!!!

Check your Time Zone settings. We had to change to our Time Zone (Lisbon).

The default value is CST6DST. Run the commad:

smit chtz_user

and change the values to GMT0WET.

Here’s a list of the values you can use: http://pic.dhe.ibm.com/infocenter/aix/v6r1/index.jsp?topic=%2Fcom.ibm.aix.files%2Fdoc%2Faixfiles%2Fenvironment.htm

I hope it was useful!!!
Cheers

Install Adobe Flash Plugin on Ubuntu 12.04 LTS Precise Pangolin

Posted by on May 9, 2012 No comments

After upgrade my Ubuntu 11.10 to the new Ubuntu 12.04 LTS almost everything worked perfectly.

The first thing I notice was that some of the shell extentions I had didn’t work (Alternate Menu). But that was not an issue.

The real issue was that the installation of Adobe Flash Player run successfully but the installation of flash plugin didn’t work that well…it raised the following error:

Failure to download extra dat file Name-or.UTF-8

After days of research, yesterday I found a question on Launchpad.net related to Ubuntu 12.04 Beta2 Adobe Flash Player Update issue.

Turns out that the solution to that issue, was the solution to my issue.

Here’s the commands to solve Adobe Flash Player Plugin installation on Ubuntu 12.04 LTS:

sudo apt-get --purge remove adobe-flash-properties-gtk adobe-flashplugin
sudo dpkg -P flashplugin-installer
sudo apt-get --purge autoremove
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install adobe-flashplugin

in Launchpad.net Answers

I hope it was useful!!!
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Install / Configure utl_mail and utl_smtp on Oracle 11g R2

Posted by on May 3, 2012 No comments

Install utl_mail/utl_smtp

[host@oracle]$ cd $ORACLE_HOME/rdbms/admin
[host@oracle]$sqlplus / as sysdba
SQL> @utlmail
SQL> @utlsmtp
SQL> @prvtmail.plb
SQL> GRANT EXECUTE ON utl_mail TO PUBLIC;
SQL> GRANT EXECUTE ON utl_smtp TO PUBLIC;
SQL> alter system set smtp_out_server='mail.server.com' scope=both;

ACL: Access Control List

in White Horses Blog

Create ACL and privileges

Now first create an ACL as SYS (or any other user with DBMS_NETWORK_ACL_ADMIN execute granted), this will hold the privileges. You can add as many privileges as you like to this file, but I would recommend to split privileges in the ACL to specific tasks or users. You must create an ACL with at least one privilege, so lets start with the ‘connect’ privilege for user SCOTT, (also a role can be added as principal):

begin
  dbms_network_acl_admin.create_acl (
    acl         => 'utl_mail.xml',
    description => 'Allow mail to be send',
    principal   => 'SCOTT',
    is_grant    => TRUE,
    privilege   => 'connect'
    );
    commit;
end;

Add Privilege

Great, now that the ACL is created, you can add more privileges like the ‘resolve’ privilege:

begin
  dbms_network_acl_admin.add_privilege (
  acl       => 'utl_mail.xml',
  principal => 'SCOTT',
  is_grant  => TRUE,
  privilege => 'resolve'
  );
  commit;
end;

Assign ACL

Cool, you granted SCOTT to connect and resolve, but you have not defined to which resources he is allowed to connect:

begin
  dbms_network_acl_admin.assign_acl(
  acl  => 'utl_mail.xml',
  host => 'smtp server host name or address'
  );
  commit;
end;

I hope it was useful!!!
Cheers

How To Resize /dev/shm Filesystem In Linux

Posted by on January 13, 2012 No comments

By default installation, RHEL and most Linux distributions mount tmpfs (a RAM-based temporarily filesystem) to /dev/shm directory and this temporarily filesystem size is always set to be half of the installed memory.

If that default size is not something expected, you can increase or reduce the /dev/shm filesystem size at wish.

To be even extreme, you may drop or disable this temporarily RAM-based filesystem entirely, to prevent it from auto-mount during system boots up, if none of the application in that Linux server relying on shared memory function or explicitly using tmpfs (as a quick-and-dirty trick to improve execution performance).

To increase or decrease /dev/shm filesystem size

1) Open /etc/fstab with vi or any text editor of your choice,

2) Locate the line of /dev/shm and use the tmpfs size option to specify your expected size,

e.g. 512MB:
tmpfs /dev/shm tmpfs defaults,size=512m 0 0
e.g. 2GB:
tmpfs /dev/shm tmpfs defaults,size=2g 0 0

The /etc/fstab content format is documented in man fstab and the tmpfs filesystem options can be found in man mount

3) To make change effective immediately, run this mount command to remount the /dev/shm filesystem:

mount -o remount /dev/shm

in Walker News

I hope it was useful!!!
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vmount: Not owner error on Linux NFS Export

Posted by on January 4, 2012 No comments

While mounting NFS filesystem from AIX node named AIX_LPAR onto Linux NFS server Linux_NFS_server, got the error:

vmount: Not owner

root [AIX_LPAR] /tmp: mount Linux_NFS_Server:/local/home/app/media /mnt
mount: giving up on:
 Linux_NFS_Server:/local/home/app/media
vmount: Not owner

Solution:

Set parameter nfs_use_reserved_ports to 1 on client AIX_LPAR

root [AIX_LPAR] /tmp: nfso -o nfs_use_reserved_ports=1
Setting nfs_use_reserved_ports to 1
root [AIX_LPAR] /tmp: mount Linux_NFS_Server:/local/home/app/media /mnt

I hope it was useful!!!
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Oracle 11gR2 Enabling and Disabling Database Options After Installation

Posted by on November 4, 2011 No comments

When you install Oracle Database, some options are enabled and others are disabled. To enable or disable a particular database feature for an Oracle home, shut down the database and use the chopt tool.

The chopt tool is a command-line utility that is located in the directory $ORACLE_HOME/bin. It uses the following syntax, where db_option is the option whose status you want to modify:

chopt [enable | disable] db_option

The possible values for db_option are:

Value Description
dm Oracle Data Mining Database Files
dv Oracle Database Vault
lbac Oracle Label Security
olap Oracle OLAP
partitioning Oracle Partitioning
rat Oracle Real Application Testing
ode_net Oracle Database Extensions for .NET 1.x
ode_net_2 Oracle Database Extensions for .NET 2.0

In this example, the chopt tool is used to enable Oracle Label Security in the database oradb1:

$ cd $ORACLE_HOME/bin
$ srvctl stop database -d oradb1
$ chopt enable lbac
$ srvctl start database -d oradb1

in Oracle 11g R2 Documentation

I hope it was useful!!!
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Disable Recycle Bin Oracle 11gR2

Posted by on September 16, 2011 No comments

To disable Recycle Bin on Oracle 11gR2 database you must change the parameter and then restart the instance:

[oracle@host]> sqlplus / as sysdba

SQL*Plus: Release 11.2.0.1.0 Production on Fri Sep 16 15:52:56 2011

Copyright (c) 1982, 2009, Oracle.  All rights reserved.

Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, Automatic Storage Management, Oracle Label Security, OLAP,
Data Mining and Oracle Database Vault options

SQL> alter system set recyclebin=OFF scope=spfile;

SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.

SQL> startup
ORACLE instance started.

Total System Global Area 3206836224 bytes
Fixed Size                  2211064 bytes
Variable Size            1795162888 bytes
Database Buffers         1392508928 bytes
Redo Buffers               16953344 bytes
Database mounted.
Database opened.

SQL> show parameter recyclebin

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
recyclebin                           string      OFF

I hope it was useful!!!
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How to drop a RAC database manually

Posted by on July 25, 2011 No comments

As we’re all used since the advent of the “new” command “drop database” on oracle, that sometimes, for a clean and total remove of oracle’s database it’s used. But if you try just use on a RAC environment, it’s necessary a little trick.

The steps are:

1) on cluster (or on the instance it self) do a:

srvctl stop database -d <databasename>

2) startup on restrict mode:

sqlplus / as sysdba

startup mount restrict exclusive;

3) The Trick !!! Change the parameter CLUSTER_DATABASE to false!!!

alter system set cluster_database=false scope=spfile;

4) restart it again restricted:

shutdown immediate;
startup mount restricted exclusive;

5) Finally: drop database !!! (becareful, it has no rollback!!!)

drop database;

6) Done !

Cheers!

Configure CheckPoint VPN SecureClient 256-bit encryption on Mac OSX Snow Leopard (10.6) 64bits

Posted by on July 21, 2011 No comments

Download CheckPoint VPN SecureClient for Mac OSX Snow Leopard (10.6) 64bits

After CheckPoint VPN SecureClient installation, open a terminal and do the following

sudo vi /opt/CPsrsc-50/database/users.C

Change the phase2_aes_key_size to 256

Save and exit users.C file.

Restart SecureClient.

 

I hope it was useful!!!
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Error remote connection to SCAN after Oracle RAC 11gR2 installation

Posted by on July 20, 2011 2 comments

If after the installation of Oracle RAC 11gR2, when you try to connect remotely you have the following error:

ORA-12545: Connect failed because target host or object does not exist

connecting on both nodes of RAC you have the following error:

ORA-12504: TNS:listener was not given the SERVICE_NAME in CONNECT_DATA

and both LISTENER and LISTENER_SCAN1 are ok.

Then look at database parameter local_listener.

If it’s pointing to one of vip name’s (NODE1-vip or NODE2-vip), change it to RAC name (RAC01)

SQL> show parameter local_listener

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
local_listener                       string      (DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=NODE1-vip)(PORT=1521))))

SQL> alter system set local_listener='(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=RAC01)(PORT=1521))))';

System altered.

SQL> alter system register;

System altered.

I hope it was useful!!!
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