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Oracle ASM Metadata Disk Utility (AMDU): View the metadata/content of asm diskgroups without mounting them

Hi,

When the ASM Diskgroups are mounted and the ASM instance is up and running you can view various dynamic views such as v$asm_diskgroup, v$asm_disk, v$asm_template etc to view the disk properties.

But, When the diskgroup is not mounted, this information is not available, which makes difficult to diagnose the errors avoiding the diskgroup to […]

ASM: Fine grained striping vs. Coarse

Hello,

We all aware that Oracle Automatic storage management offers striping of disks but propreitory of its own method.

To stripe data, Oracle ASM separates files into stripes and spreads data evenly across all of the disks in a disk group. It has two methods of striping, Fine & Coarse.

Fine Striping:- Fine striping writes […]

Oracle RAC: Load Balancing advisory concepts

Oracle 10gR2 provides an advanced load balancing method to overcome the imbalance of RAC logon’s , especially when there is logon storms, the listeners on the two nodes will simply distribute them evenly across both the nodes. Some case one of the node can be busier than the other . The LBA will calculate how […]

RAC: Client & Server connection Load balancing in Oracle

Connection Workload management is one of the key aspects when you have RAC instances as you want to distribute the connections to specific nodes/instance or those have less load.

Oracle from 10g onwards (9i as well) has two features to provide the connection load balancing

Client Side load balancing (also called as connect time load […]

Quick Question #14: Why do we have Virtual IP in Oracle RAC

Why do we have a Virtual IP (VIP) in Oracle RAC 10g or 11g? Why does it just return a dead connection when its primary node fails?

The goal is application availability with the shortest disruption time possible.

When a node fails, the VIP associated with it is automatically failed over to some other […]

Lib32 folder missing in Oracle 11g Home

One of my colleague struggling from two days for a Oracle client 11g 64 bit installation, where he is expecting a lib32 folder in Oracle_HOME as usual but he didn’t.  Thanks to him first for sharing before to proceed further.

He didn’t succeeded to get lib32 folder instead he found this note, which may save […]

Troubleshoot ORA-00020: maximum number of processes exceeded – Systematic way

Situation: Application not able to connect and including sysdba sessions. Complete DB hung due to large number of session spike in very less time.

Error:-ORA-00020: maximum number of processes exceeded

Dependent parameters sessions = 825 processes = 800

Action taken, We have killed some backups jobs and other local sessions and get a slot of […]

Explain Plan: Different formats/options with dbms_xplan

The DBMS_XPLAN package provides an easy way to display the output of the EXPLAIN PLAN command in several, predefined formats. You can also use the DBMS_XPLAN package to display the plan of a statement stored in the Automatic Workload Repository (AWR) or stored in a SQL tuning set. It further provides a way to display […]

Unix: Top 10 useful SAR commands in unix, performance monitoring using SAR

The following are the top 10 Useful SAR commands for DBA’s.

1. CPU Usage of ALL CPUs (sar -u)

This gives the cumulative real-time CPU usage of all CPUs. “1 3″ reports for every 1 seconds a total of 3 times. Most likely you’ll focus on the last field “%idle” to see the cpu […]

Unix: Performance tools available for you

This is beginning of Unix series post for DBA’s to understand the monitoring tools for Linux

Sysstat is the package that contains various tools or utilities to collect or view the performance of the Unix servers.

Installing sysstat

wget http://pagesperso-orange.fr/sebastien.godard/sysstat-10.0.0.tar.bz2

tar xvfj sysstat-10.0.0.tar.bz2

cd sysstat-10.0.0

./configure –enable-install-cron

make

make install

Verify

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