Job Priorities and Priority Precedence

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Overview

Job Priority Numbers

Set Job Priorities

View Job Priorities

Change Job Priorities

Supported Agents


Overview

Job priorities determine which competing jobs can access limited resources (such as drives and media). When a job is started, the Job Manager assigns the job a priority number. The lower the job priority number, the higher the priority. The job with the highest priority gets the resources first. The priority of a job is based on the:

When several jobs have the same priority, resources are allocated on a first-come, first-served basis. When a job is completed, then the Job Manager automatically assigns the newly freed resources to the next job.

When several jobs have a different priority, if job preemption is allowed, the Job Manager will interrupt the running job and then allocate the resources to the higher priority job.

The priorities of jobs (except data aging and export media) can also be changed when they are being initiated, scheduled, or are active.


Job Priority Numbers

Job Priorities are based on a 3-digit integer. The first digit always represents operation priority. If client precedence is chosen, the second digit represents client priority and the third digit represents agent priority. If agent precedence is chosen, the second digit represents agent priority and the third digit represents client priority.

Operation Priority

Operation priorities (the first digit of the job priorities number) are assigned by the Job Manager and can be changed using the Change Job Priority feature. The operation priority assignments are:

Operation Assigned Priority
Data Recovery Operations 0
Data Protection Operations 1

Client Computer Priority

The Job Manager automatically assigns a priority of 6 to all client computers. Therefore, the Job Manager evaluates all client computers as having the same priority. Based on this assumption, you may want to change the client priority.

For example, you may want operations originating from a specific file server to take precedence over operations originating from a userís computer. To do this, you would assign a file server a higher priority than other computers within the CommCell.

Agent Priority

The Job Manager automatically assigns a priority of 6 to all agents. Therefore, the Job Manager evaluates all agents as having the same priority. Based on this assumption, you may want to change the priority of agents.

For example, you may want Exchange database operations to take precedence over Windows 2000 File System operations. To do this, you would assign the Exchange Database iDataAgent a higher priority than the Windows 2000 File System iDataAgent.

To illustrate this point further, suppose you have chosen client precedence and you run a data protection operation with a client that has a priority of two and an agent with a priority of three, then the 3-digit integer will look like this:

Job Priority Exceptions

The following table lists jobs that do not follow the job priorities rules listed above. The priorities of all administration jobs, with the exception of auxiliary copy jobs, cannot be changed. However, the priority of an auxiliary copy job can be changed using the Change Job Priority feature.

Operation Assigned Priority
Data Aging, Export Media Not applicable
Inventory, Download Updates, Install Updates 0
Disaster Recovery Backups 66
Data Verification 366
Erase Media 466
Auxiliary Copy 266

NOTES

A search inventory job is of highest priority.


Set Job Priorities

You can set the job priority of an agent or client.

Set the Priority of an Agent

From the CommCell level, the priority of an agent can be set from the Priority column of the Job Priorities pane of the General tab of the Job Management dialog box.

Set the Job Priority of a Client

From the Client level, the priority of a client can be changed from the Job Priority (0-9)field of the Job Configuration tab of the Client Computer Properties dialog box.


View Job Priorities

You can view the priority of a specific job by viewing the details of the job, or you can view the priority of all jobs in the job controller. By default, the Job Controller window does not display the priorities of running jobs. To view the job priorities for all jobs, you need to enable the Priority column.


Change Job Priorities

The Change Job Priority feature allows you to change the priority of a job or groups of jobs. Using this feature may be necessary if you need to change the priority of jobs based on how you want the Job Manager to allocate necessary resources. Note that if you change the priority of job because you want that job to interrupt another job for resources, that job must be able to preempt the other job.

This feature allows you to:

Types of Jobs That Can Be Changed

You can change the job priority number of the following jobs:

Change Job Priorities From the Job Controller

The priority of a job or groups of jobs can be changed from the Change Job Priority dialog box.

Change the Priority of an Individual Job Being Submitted

The priority of a job that is being submitted immediately or is being scheduled can be changed from the Change Priority dialog box.

Priority Precedence

By default, client computers (the second digit in the job priority number) have higher precedence over agents (the third digit in the priority number). You can reverse the order of the digits so that the agent has priority over the client computer.

You can change the priority precedence of a client or agent from the General tab of the Job Management dialog box.


Supported Agents

All agents support the Change Priority feature except the following agent:


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