Exadata Storage Server Management

About Exadata Storage Server

An Exadata Storage Server is a highly optimized storage server that runs Oracle Exadata System Software to store and access Oracle Database data. Use the Exadata Storage Server Home page to manage and monitor the Oracle Exadata Storage Server as an Enterprise Manager Cloud Control target. You can discover and consolidate management, monitoring and administration of a single or a group of Oracle Exadata Storage Servers in a datacenter using Enterprise Manager.

Note:

As the Exadata Database Machine has evolved, there have been different names used to reference the Exadata Storage Server, including storage cell and cell server. Any reference with these names in this or related documentation refers to Exadata Storage Server.

Exadata Storage Servers can be discovered automatically or manually. The individual Exadata Storage Server is monitored and managed as an Enterprise Manager target and provides the exception, configuration and performance information.

Grouping of Exadata Storage Servers is used for easy management and monitoring a set of Storage Servers. You can group them both manually and automatically. The grouping function provides an aggregation of exceptions, configuration and performance information of the group of Exadata Storage Servers.

You can view performance analysis by linking Exadata performance both at the Exadata Storage Server level and group level to ASM and database performance. You can drill down to Exadata configuration and performance issues from both the database and ASM targets.

Storage Grid (for example, multiple database/ASM instances sharing the same Exadata Storage Server) is supported to the same extent as dedicated storage.

Viewing an Exadata Storage Server Topology

You can view the topology of an Oracle Exadata Storage Server target by following the steps below:

Navigate to the Exadata Storage Server home page by choosing the Exadata target for which you want to view the configuration.

Enterprise Manager displays the Exadata Storage Server Home page for the target you selected.
From the Target menu, choose Configuration and then Topology.
Enterprise Manager displays the Configuration Topology page for the selected Exadata Storage Server. The topology page provides a visual layout of the target's relationships with other targets. From this page you can:
- Do a target search filtered by target status/events/target type
- Select from a set of relationships to represent in the graph
- Select annotations to display in the graph, such as alerts and link labels
- Select from a set of options: view navigator, expand or collapse all, toggle graph layout, reload topology
- Print
- Zoom via the slide control
- Pan via the navigator control
- Toggle the presentation from graph to table
When you hover over a node or group member, a popup displays detailed information about the entity. A link can appear in the popup to more detailed information such as customer documentation.

Performing Administration Tasks on Exadata Storage Servers

Note:

It is best practice to manage and configure Exadata Storage Servers consistently. Enterprise Manager provides the ability to perform Administration Tasks on all Exadata Storage Servers in an Exadata Database Machine from the corresponding Exadata Storage Server Grid target home page, or on individual Exadata Storage Server targets from the Exadata Storage Server target home page. To the maximum extent possible, consider managing from the Exadata Storage Server Grid target to manage the servers consistently, selecting a subset of servers if necessary. The instructions in this section can be used for either the Exadata Storage Server Grid or Exadata Storage Server targets.

To perform an administration operation on an Exadata Storage Server, such as executing a Exadata Storage Server command, follow these steps:

Navigate to the Exadata Storage Server home page by choosing the Exadata target for which you want to perform an administrative task from the All Targets page.

Enterprise Manager displays the Exadata Storage Server Home page for the target you selected.
Click Exadata Storage Server, and then select Administration.

From this menu you can choose either Execute Cell Command, or Manage I/O Resource.
Click Execute Cell Command.

The Command page of the Exadata Storage Servers Administration wizard appears. Enter a CELLCLI command as the administrative command to be executed on the Exadata Storage Server. You must read the Command Instructions before you enter a command. Only a single cellCLI command is allowed to execute. You must enter the command without the cellcli -e prefix, which is automatically appended when you submit the command. Finally, you cannot use the following characters: ; / ' < > / |.
Click Next to continue.

Enterprise Manager displays the Admin Credentials page. Select or enter the Administration credentials to execute the command. The credentials you enter are used when submitting the operation. You can choose between Preferred Credentials, Named Credentials, and New Credentials. You can also click More Details to view information about Credential Type, Last modified, Credential Name, Credential Owner, Last Modified Date, Last Modified By, and Preferred Credentials Set At.
Click Next.

Enterprise Manager displays the Schedule page. Use the Schedule page to schedule the administration task. Enter the Job Name and the Job Description, then provide the job information in the Schedule the Administration Job section. You can choose to begin the job immediately or enter the time you want the job to begin.
Click Next to continue.

The Summary page displays. Use the Summary page to ensure you have entered the correct values and then submit the command. The Summary page lists the Job Name, Description, Command to Execute, when the job is Scheduled, and the Selected Cell.
Click Submit Command to submit the job.

The Job Status page displays. Use the Job Status page to link to the Job Detail page of the administration task.

Managing the I/O Resource

Oracle Exadata Storage Servers are added as targets during the Exadata Database Machine discovery workflow (see Exadata Database Machine Discovery) and are grouped automatically under the group Exadata Storage Server Grid. Monitoring and Managing I/O Resource can be performed at Exadata Storage Server Grid and Exadata Storage Server target level. The information provided below is for Grid and Server target.

To access the IORM Performance page:

Select an Exadata Storage Server:
1. From the Targets menu, select Exadata.
2. Select a DB Machine from the list of Target Names.
3. In the Target Navigation pane, expand the Exadata Grid item and click one of the Exadata Storage Servers.
Once you have selected an Exadata Storage Server, click the Exadata Storage Server menu, select Administration, then Manage I/O Resource.

The IORM page has the following sections:

I/O Resource Manager Settings: This section helps to view and update the IORM configuration of Exadata Storage Server. Use Get Latest button to view the latest Exadata Storage Server IORM configuration. Use the same section to edit and update the IORM configuration on Exadata Storage Server.
Database Resource Management(DBRM) Settings: This section display the list of databases and their basic configuration, that are using Exadata Storage Server resources. From this page, you can launch the database resource management page.
Workload Distribution by Databases: The IORM Monitoring section of the page provides a view of the performance statistics of Disk I/O (Wait, IOPS, MBPS, Utilization, Latency, and Objective charts). These statistics help to identify which databases and consumer groups are using the available resources. They also help to adjust the IORM configuration (using IORM Settings section on the same page) as needed.

IORM Configuration includes IORM Objective and Inter-Database Plan.

For further details on managing I/O resources, refer to the Managing I/O Resources chapter in the Oracle® Exadata Storage Server Software User's Guide.

Add/Update IORM Configuration

To update the I/O Resource Manager (IORM) settings (for Exadata Storage Server software release 12.1.2.1.0 and later):

Navigate to the IORM page as described above. The image shows the I/O Resource Manager (IORM) Settings pane.

Note:

You can also update a single Exadata Storage Server. Expand the Exadata Grid group to view all Exadata Storage Servers associated with the group. Click the Exadata Storage Server you want to update.

The steps to update the IORM settings is the same for a single Exadata Storage Server or group of Exadata Storage Servers.
Update the inter-database plan by editing existing values or add/remove directives to Inter-database plan using the Add/Remove buttons available on Inter-database table.
1. From the Database Name column, select a database from the drop-down menu or enter a database name.
2. Enter a value for the Hard Disk I/O Utilization Limit column.
3. Enter a value for the Database I/O Share column.
4. Enter minimum and maximum values (in MB) for the Flash Cache column.
5. Fill the remaining attributes like Type and Role.
In the Disk I/O Objective drop-down menu, select an objective from the list (Auto is the default):
- Low Latency - Use this setting for critical OLTP workloads that require extremely good disk latency. This setting provides the lowest possible latency by significantly limiting disk utilization.
- Balanced - Use this setting for critical OLTP and DSS workloads. This setting balances low disk latency and high throughput. This setting limits disk utilization of large I/Os to a lesser extent than Low Latency to achieve a balance between good latency and good throughput.
- High Throughput - Use this setting for critical DSS workloads that require high throughput.
- Auto - Use this setting to have IORM determine the optimization objective. IORM continuously and dynamically determines the optimization objective, based on the workloads observed, and resource plans enabled.
- Basic - Use this setting to disable I/O prioritization and limit the maximum small I/O latency.
Note:
If the Auto and Balanced objectives are not applicable (i.e., they have no impact on I/Os in Extreme Flash Exadata Storage Servers), they will not appear in the IORM page.

Click Update. The Exadata Storage Server Administration Wizard will appear prompting you for the information necessary to complete the Disk I/O Objective configuration:
1. On the wizard's Command page, the Cell Control Command-Line Interface (CellCLI) value should be as shown when the Disk I/O Objective selected is auto:
```
# alter iormplan objective = 'auto'
```
  Click Next.
2. On the wizard's Admin Credentials page, enter the user name and password for the selected Exadata Storage Servers.
  
  Click Next.
3. On the wizard's Schedule page, enter a job name (required) and job description (optional). Select an option to start Immediately or Later. If you select the Later option, enter the time that you want the job to run.
  
  Click Next.
4. On the wizard's Review page, verify that the settings are correct. To submit the command, click Submit Command.
  
  After the job is successfully submitted, the Job Status page is displayed.
  
  Click Return to return to the I/O Resource Manager (IORM) Settings pane.
Click Get Latest to refresh the IORM configuration from Exadata Storage Server, which will include the updated Disk I/O Objective.
To confirm the Disk I/O Objective setting, for example if it was selected as auto, run the following command from the command line:
```
# dcli -g cell_group cellcli -e "list iormplan attributes objective"
```
Output should show the value auto:
```
cell01: auto
cell02: auto
cell03: auto
.
.
.
cell14: auto
```

The Inter-Database Plan

An inter-database plan specifies how resources are allocated by percentage or share among multiple databases for each Exadata Storage Server. The directives (rows) in an inter-database plan specify allocations to databases, rather than consumer groups. The inter-database plan is configured and enabled with the CellCLI utility at each Exadata Storage Server. Only one inter-database plan can be active on a Exadata Storage Server at any given time.

Percentage based Inter-database plan: Use allocations to specify percentage for I/O distribution for each database. With Percentage based plan, IORM can manage up to 32 databases. You can allocate resources across 8 different levels. A percentage based inter-database plan is similar to a database resource plan, in that each directive consists of an allocation amount and a level from 1 to 8. For a given percentage based plan, the total allocations at any level must be less than or equal to 100 percent. An inter-database plan differs from a database resource plan in that it cannot contain sub-plans and only contains I/O resource directives.

Share based inter-database plan: This is the recommended method for Inter-database plans. Use share to specify the relative priority for a database. A higher share value implies higher priority and more guaranteed I/O resources. Each database is given a share value which is an integer between 1 and 32. Use the limit method to restrict the I/O utilization for a database to a specified utilization limit. The sum of the shares can be greater than 100. Share-based plans support up to 1024 directives within the Inter-database plan.

I/O Resource Management can provide predictable performance by guaranteeing space in Exadata Smart Flash Cache. For this use Flash Cache Space columns to specify space allocation for each database in Inter-database plan.

Specify the attributes values for each directive in Inter-database plan as per requirement.

Note:

If the Exadata Storage Server version is 11.2.3.1.0 or earlier, the Share, Percentage based inter-database plan radio buttons are not available. You can view only Percentage-based options (that is, the drop-down only displays the Basic, Advance options).

When considering an inter-database plan:

If Oracle Exadata Storage Server is hosting only one database, then an inter-database plan is not needed.
If an inter-database plan is not specified, then all the databases receive an equal allocation.

Diagnosing Exadata Storage Server Alerts

Enterprise Manager listens for Exadata Storage Server alerts sent from the Exadata Storage Server Management Server; so, any hardware failure or Exadata Storage Server error will be reported in Enterprise Manager. For information about the error messages you might encounter on the Exadata Database Machine, refer to the Error and Alert Messages in Oracle Exadata Database Machine Error Message Reference Guide.