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Note: All the posts are based on practical approach avoiding lengthy theory. All have been tested on some development servers. Please don’t test any post on production servers until you are sure.

Thursday, October 31, 2013

Exadata: Health Checking Exadata (Exachk)

Oracle’s exachk utility (NON-INTRUSIVE and does not change anything in the environment) is designed to perform a comprehensive health check of Exadata Database Machine. It is designed to audit important configuration settings within an Oracle Exadata Database Machine. The components examined are database servers, storage Servers, InfiniBand fabric, InfiniBand Switches, and Ethernet network.
exachk should be executed (under Oracle Software owner on DB node) after the initial Oracle Exadata Database Machine deployment, as part of the routine maintenance schedule (at least monthly), and before and after any system configuration change. You should run only one exachk instance at a time.

Exadata: Understanding key OS Processes for a cell

Exadata' s unique software runs different processes on OS to perform different functions. There are three main programs that run on the Exadata Storage Servers to facilitate cell operations cellsrv, MS and RS.  You can identify the OS processes by using ps.

Wednesday, October 30, 2013

Exadata: What differentiates GI on Exadata with GI on non-Exadata?

The installation,configuration, and administration of Grid Infrastructure on Exadata is identical to Grid Infrastructure on non-Exadata systems. On Exadata, Oracle has elected to store the Oracle Cluster Registry (OCR) and voting disks on Oracle ASM disk groups, mapped to Exadata storage server grid disks. Most processes in Exadata’s Oracle 11gR2 Grid infrastructure perform the same functions as non-Exadata 11gR2 installations, but one software component that plays a special role in Exadata environments is the diskmon process and associated processes

Exadata: Get Cell statistics quickly

Some time you want to get the quick information about Cell like offloading, Storage index etc. Exadata cell has a small tool named as cellsrvstat which provides the comprehensive information like below

Tuesday, October 29, 2013

Exadata: Replacing damaged disk is really plugNplay activity

On Exadata if any disk is failed due to some problem , replacing it will not be the hard job. It is quite simple task. On my testing environment I did the below to test it, things are quite self explanatory.

Monday, October 28, 2013

Exadata: Monitoring Active Requests, Alerts and Wait Events

Active request provides a client-centric or application-centric view of client I/O requests that are currently being processed by a cell. An active request is characterized at all levels: instance, database, ASM, and cell.

Alerts represent events of importance occurring within the storage cell, typically indicating that storage cell functionality is either compromised or in danger of failure.An alert is automatically triggered when a predefined hardware or software issue is detected, or when a metric exceeds a threshold.
Alert history entries are retained for a maximum of 100 days. If the number of alert history entries exceeds 500, then the alert history entries are only retained for 7 days. 
Stateful alerts represent observable cell states that can be subsequently retested to detect whether the state has changed, indicating that a previously observed alert condition is no longer a problem.
Stateless alerts represent point-in-time events that do not represent a persistent condition; they simply show that something has occurred.

Exadata: Monitoring Performance (Using Metrics)

Like database  in Exadata Metrics and alerts also help you monitor Oracle Exadata Storage Server Software. Metrics are associated with objects such as cells and cell disks, and can be cumulative, rate, or instantaneous.
Metrics are recorded observations of important run-time properties, retained in memory and stored on a disk for a more permanent history.

Exadata: Implementing Cell Security

Security for Exadata Cell is enforced by identifying which clients can access cells and grid disks. Clients include Oracle ASM instances, database instances, and clusters. By default Exadata allows all ASM clusters and databases in the system access to all grid disks. You can implement cell security control access to grid disks at two levels, by ASM cluster and by database