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Workload Management Reference

 

Applies to: Exchange Server 2013, Exchange Online

Topic Last Modified: 2013-06-13

In Microsoft Exchange Server 2013, Exchange workloads are throttled based on the health of specific system resources. When specific system resources reach unhealthy levels, Exchange uses a configurable classification system based on policy settings to make sure that each Exchange workload is able to consume the appropriate amount of system resources. This topic contains information about the Exchange workloads and system resource thresholds.

Exchange workloads are managed by default workload management policy settings that are installed during Exchange Server 2013 Setup. You can make global changes to the default settings that apply to all the servers in your organization. You can also make changes to workload management settings on specific servers in your organization. For more information, see Exchange Workload Management.

Contents

Knowledge of the following terms will help you understand the information referenced in this topic.

Exchange workload

An Exchange workload is an Exchange server feature, protocol, or service that has been explicitly defined for the purposes of Exchange system resource management. Each Exchange workload consumes system resources such as CPU, mailbox database operations, or Active Directory requests, to run user requests or background work. Examples of Exchange workloads include Outlook Web App, Exchange ActiveSync, mailbox migration, and Managed Folder Assistant.

Workload classification

A workload classification specifies the default priority of each Exchange workload. A workload can be assigned one of the following classifications: Urgent, Customer Expectation, Internal Maintenance, and Discretionary.

System resource health indicator

A system resource health indicator is used to measure the health of a specific component on an Exchange server. The system resource health indicators that have been defined for the purposes of Exchange system resource management include CPU, mailbox RPC latency, and mailbox replication latency. Exchange workloads are throttled based on one or more of the available system health indicators.

System resource thresholds

A system resource threshold represents a configurable limit for a system resource. Each Exchange workload classification has three different configurable thresholds. The thresholds define the underloaded, overloaded, and critical levels for each system resource.

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The following table shows the default Exchange 2013 workload policies and the default classification for each workload. To review the default threshold value for each system resource health indicator based on workload classification, see the section “System resource thresholds”.

noteNote:
You can view the workload policies and workload classifications that are currently set up in your environment using the Exchange Management Shell. To review the values for all Exchange 2013 workloads, from the Shell, run Get-WorkloadPolicy.

The following are the Exchange workloads and their default classifications.

 

Workload policy name Description Workload classification

MailboxReplicationServiceHighPriority

Mailbox Replication service high priority

Urgent

StoreUrgentMaintenanceAssistant

Store Maintenance Assistant

Urgent

Eas

Exchange ActiveSync

Customer expectation

JunkEmailOptionsCommitterAssistant

Junk email

Customer expectation

MailboxProcessorAssistant

Mailbox Processor Assistant

CustomerExpectation

PowerShellBackSync

Windows PowerShell BackSync operations

Customer expectation

PowerShellForwardSync

Windows PowerShell FwdSync operations

Customer expectation

PublicFolderMailboxSync

Public folder mailbox synchronization

Customer expectation

TeamMailboxSync

Site mailbox synchronization

Customer expectation

Transport

Transport mail flow

Customer expectation

CalendarRepairAssistant

Calendar Repair Assistant

Internal maintenance

CalendarSyncAssistant

Calendar Synchronization Assistant

Internal maintenance

ContactLinkingAssistant

Contact Linking Assistant

Internal maintenance

DirectoryProcessorAssistant

Directory Processor Assistant

Internal maintenance

Domt

Address book

Internal maintenance

ELCAssistant

Managed Folder Assistant

Internal maintenance

Ews

Exchange Web Services

Internal maintenance

Imap

IMAP4

Internal maintenance

Momt

RPC Client Access and Outlook

Internal maintenance

OABGeneratorAssistant

Offline Address Book Generation Assistant

Internal maintenance

OrgContactsSyncAssistant

Organizational Contacts Synchronization Assistant

Internal maintenance

Owa

Outlook Web App

Internal maintenance

OwaVoice

Outlook Web App Voice Access

Internal maintenance

PeopleRelevanceAssistant

People Relevance Assistant

Internal maintenance

Pop

POP3

Internal maintenance

PowerShell

Windows PowerShell work that’s not included in the other Windows PowerShell workloads

Internal maintenance

PowerShellGalSync

Windows PowerShell work related to global address list synchronization

Internal maintenance

PowerShellLowPriorityWorkFlow

Windows PowerShell work that’s generally not time sensitive

Internal maintenance

PushNotificationService

Push Notification service

Internal maintenance

SharingPolicyAssistant

Sharing Policy Assistant

Internal maintenance

SiteMailboxAssistant

Site Mailbox Assistant

Internal maintenance

StoreMaintenanceAssistant

Store maintenance

Internal maintenance

StoreOnlineIntegrityCheckAssistant

Store Online Integrity Check Assistant

Internal maintenance

TopNAssistant

Top N Words Assistant

Internal maintenance

TransportSync

Transport synchronization

Internal maintenance

UMReportingAssistant

Unified Messaging Reporting Assistant

Internal maintenance

InferenceDataCollectionAssistant

Inference Data Collection Assistant

Discretionary

InferenceTrainingAssistant

Inference Training Assistant

Discretionary

MailboxReplicationService

Mailbox Replication service

Discretionary

PowerShellDiscretionaryWorkFlow

Windows PowerShell work that’s generally not time sensitive

Discretionary

PublicFolderAssistant

Public folders

Discretionary

StoreScheduledIntegrityCheckAssistant

Store Scheduled Integrity Check Assistant

Discretionary

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The following tables show the default thresholds for each of the five system resources that are used to throttle Exchange workloads. Three thresholds (underloaded, overloaded, and critical) are defined for each system resource. The thresholds that apply to a system resource depend on the workload classification assigned to the workload (workload classifications include: discretionary, internal maintenance, customer expectation, and urgent).

noteNote:
You can view the system resource threshold settings that are currently set up in your environment using the Exchange Management Shell. To review the Exchange 2013 threshold values, from the Shell, run Get-ResourcePolicy | format-list.

The following are the system resources and their default thresholds.

Active Directory Replication Latency

 

Workload classification Threshold Seconds

Discretionary

Underloaded

5

Discretionary

Overloaded

20

Discretionary

Critical

45

Internal Maintenance

Underloaded

5

Internal Maintenance

Overloaded

25

Internal Maintenance

Critical

45

Customer Expectation

Underloaded

5

Customer Expectation

Overloaded

30

Customer Expectation

Critical

50

Urgent

Underloaded

5

Urgent

Overloaded

60

Urgent

Critical

100

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Local Server CPU (Processor)

 

Workload classification Threshold Percent

Discretionary

Underloaded

70

Discretionary

Overloaded

80

Discretionary

Critical

100

Internal Maintenance

Underloaded

75

Internal Maintenance

Overloaded

85

Internal Maintenance

Critical

100

Customer Expectation

Underloaded

80

Customer Expectation

Overloaded

90

Customer Expectation

Critical

100

Urgent

Underloaded

100

Urgent

Overloaded

100

Urgent

Critical

100

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Mailbox Database RPC Latency (MDBLatency)

 

Workload classification Threshold Milliseconds

Discretionary

Underloaded

10

Discretionary

Overloaded

20

Discretionary

Critical

70

Internal Maintenance

Underloaded

10

Internal Maintenance

Overloaded

20

Internal Maintenance

Critical

70

Customer Expectation

Underloaded

15

Customer Expectation

Overloaded

30

Customer Expectation

Critical

70

Urgent

Underloaded

25

Urgent

Overloaded

50

Urgent

Critical

100

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Mailbox Database Replication Health (MdbReplication)

 

Workload classification Threshold Bytes

Discretionary

Underloaded

2097152

Discretionary

Overloaded

3145728

Discretionary

Critical

6291456

Internal Maintenance

Underloaded

2097152

Internal Maintenance

Overloaded

3145728

Internal Maintenance

Critical

7340032

Customer Expectation

Underloaded

2097152

Customer Expectation

Overloaded

3145728

Customer Expectation

Critical

8388608

Urgent

Underloaded

2097152

Urgent

Overloaded

3145728

Urgent

Critical

9437184

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Content Indexing Age of Last Notification (CiAgeOfLastNotification)

 

Workload classification Threshold Seconds

Discretionary

Underloaded

10

Discretionary

Overloaded

15

Discretionary

Critical

180

Internal Maintenance

Underloaded

10

Internal Maintenance

Overloaded

15

Internal Maintenance

Critical

180

Customer Expectation

Underloaded

10

Customer Expectation

Overloaded

15

Customer Expectation

Critical

180

Urgent

Underloaded

10

Urgent

Overloaded

15

Urgent

Critical

180

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Content Indexing Retry Queue Size (CiRetryQueueSize)

 

Workload classification Threshold Items

Discretionary

Underloaded

540

Discretionary

Overloaded

1080

Discretionary

Critical

2700

Internal Maintenance

Underloaded

540

Internal Maintenance

Overloaded

1080

Internal Maintenance

Critical

2700

Customer Expectation

Underloaded

540

Customer Expectation

Overloaded

1080

Customer Expectation

Critical

2700

Urgent

Underloaded

540

Urgent

Overloaded

1080

Urgent

Critical

2700

Mailbox Database Availability Health (MdbAvailability)

 

Workload classification Threshold Bytes

Discretionary

Underloaded

2097152

Discretionary

Overloaded

3145728

Discretionary

Critical

6291456

Internal Maintenance

Underloaded

2097152

Internal Maintenance

Overloaded

3145728

Internal Maintenance

Critical

7340032

Customer Expectation

Underloaded

2097152

Customer Expectation

Overloaded

3145728

Customer Expectation

Critical

8388608

Urgent

Underloaded

2097152

Urgent

Overloaded

3145728

Urgent

Critical

9437184

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