Workload Management in Exchange 2013

Workload Management (WLM) is a great new feature that was introduced with Exchange 2013 (well, ok to be fair Exchange 2010 introduced the concept of User throttling. Exchange 2013 simply builds on that). The function of WLM is basically to preserve the user experience by throttling other processes. It is comprised of both User-based throttling (not discussed on this post as it is detailed on TechNet fairly well) and System throttling. To achieve this, different workloads in Exchange are assigned different priorities. For example, mailbox moves are a lower priority workload than, say, Transport (after all, it IS important to get that new email from your favorite coupon site, right?!?).

Starting with RTM and up through CU5, managing System Workload Management settings were available via the following cmdlets

*-ResourcePolicy
*-WorkloadManagementPolicy
*-WorkloadPolicy

WorkloadPolicy defined the classifications for various different workloads. Examples of Classifications include InternalMaintenance, CustomerExpectation, Discretionary and Urgent.

ResourcePolicy defined the Thresholds for the various classifications upon which those workload types would begin to be throttled (micro-delayed).

WorkloadManagementPolicy simply links the two together.

However, starting with CU6, these cmdlets disappeared, and the TechNet links were removed and replaced with this simple statement found here

Note:

The *-ResourcePolicy, *-WorkloadManagementPolicy and *-WorkloadPolicy system workload management cmdlets have been deprecated. System workload management settings should be customized only under the direction of Microsoft Customer Service and Support.

That is all fine and good (after all, I work in CSS!). But for a while, even I didn’t know how to view what the current settings were!!!

Alas – nothing (well, ALMOST nothing) can remain hidden forever. And so I found that the System workload management settings are now visible by using Get-ExchangeDiagnosticInfo. Now I do want to add a caveat here that this blog post will not provide information on how to modify System Workload Policies. However, I felt like it was important to be able to view what the current settings are so that you can understand why certain workloads might end up getting throttled.

If you haven’t already had the pleasure of using Get-ExchangeDiagnosticInfo, there is a lot of information available. I won’t delve in to everything that can be retrieved, but rather will focus on the System Workload policy-related information.

The general syntax to view System Workload policy information is

Get-ExchangeDiagnosticInfo –server <server> -process MSExchangeMailboxAssistants –Component SystemWorkloadManager –Argument policy

However – you will probably notice that the output from this cmdlet is XML format, which is, well, ugly to read. Lets clean it up a little, shall we? Define a variable for your command, and specify the format as XML so Powershell can format it.

[xml]$diag = Get-ExchangeDiagnosticInfo –server <server> -process MSExchangeMailboxAssistants –Component SystemWorkloadManager –Argument policy

Now that we have the data stored in memory, we can look at the components. The Policy is actually comprised of several sub-components. Lets look at the Resource policy portion first. This shows the Metric types (core resources that we measure the health of)

$diag.diagnostics.components.systemworkloadmanager.policy.resourcepolicy

MetricType	MaxConcurrency	ResourceMetricPolicy
ActiveDirectoryReplicationLatency	1024	{ResourceMetricPolicy,
MdbLatency	3	{ResourceMetricPolicy,
Processor	1024	{ResourceMetricPolicy,
MdbReplication	3	{ResourceMetricPolicy,
CiAgeOfLastNotification	3	{ResourceMetricPolicy,
MdbAvailability	3	{ResourceMetricPolicy,
DiskLatency	10	{ResourceMetricPolicy,

Now notice that the ResourcePolicy actually has a property that is multivalued. We can look at that in more detail and see that each metric type has different values for each classification type. This is what allows workloads with a classification of a higher priority to continue working while those with a lower priority are throttled (micro-delayed).

$diag.diagnostics.components.systemworkloadmanager.policy.resourcepolicy.resourcemetricpolicy | ft

MetricType	Classification	UnderloadedThreshold	OverloadedThreshold	CriticalThreshold
ActiveDirectoryReplicationLatency	Discretionary	5	25	45
ActiveDirectoryReplicationLatency	InternalMaintenance	5	25	45
ActiveDirectoryReplicationLatency	CustomerExpectation	5	30	50
ActiveDirectoryReplicationLatency	Urgent	5	60	100
MdbLatency	Discretionary	10000	20000	70000
MdbLatency	InternalMaintenance	10000	20000	70000
MdbLatency	CustomerExpectation	15000	30000	70000
MdbLatency	Urgent	25000	50000	100000
Processor	Discretionary	70	80	100
Processor	InternalMaintenance	75	85	100
Processor	CustomerExpectation	80	90	100
Processor	Urgent	100	100	100
MdbReplication	Discretionary	2097152	6291456	52428800
MdbReplication	InternalMaintenance	2097152	6291456	52428800
MdbReplication	CustomerExpectation	2097152	6291456	52428800
MdbReplication	Urgent	2097152	6291456	52428800
CiAgeOfLastNotification	Discretionary	60	180	240
CiAgeOfLastNotification	InternalMaintenance	120	180	300
CiAgeOfLastNotification	CustomerExpectation	180	240	600
CiAgeOfLastNotification	Urgent	240	300	600
MdbAvailability	Discretionary	11534336	105906176	1048576000
MdbAvailability	InternalMaintenance	11534336	105906176	1048576000
MdbAvailability	CustomerExpectation	11534336	105906176	1048576000
MdbAvailability	Urgent	11534336	105906176	1048576000
DiskLatency	Discretionary	10	20	30
DiskLatency	InternalMaintenance	10	20	30
DiskLatency	CustomerExpectation	10	20	30
DiskLatency	Urgent	50	50	50

Finally, we can view the workload policy, which provides the list of each defined workload type and the respective classification.

$diag.diagnostics.components.systemworkloadmanager.policy.workloadpolicy

WorkloadType	Classification	MaxConcurrency
MailboxReplicationService	Discretionary	1024
ELCAssistant	InternalMaintenance	1024
JunkEmailOptionsCommitterAssistant	CustomerExpectation	1024
CalendarRepairAssistant	InternalMaintenance	1024
SharingPolicyAssistant	InternalMaintenance	1024
TopNAssistant	InternalMaintenance	1024
CalendarSyncAssistant	InternalMaintenance	1024
UMReportingAssistant	InternalMaintenance	1024
InferenceTrainingAssistant	InternalMaintenance	1024
StoreMaintenanceAssistant	InternalMaintenance	1024
PublicFolderAssistant	Discretionary	1024
DirectoryProcessorAssistant	InternalMaintenance	1024
PowerShell	InternalMaintenance	1024
PowerShellForwardSync	CustomerExpectation	1024
PowerShellBackSync	CustomerExpectation	1024
PowerShellGalSync	InternalMaintenance	1024
PowerShellLowPriorityWorkFlow	InternalMaintenance	1024
PowerShellDiscretionaryWorkFlow	Discretionary	1024
OABGeneratorAssistant	CustomerExpectation	1
Ews	InternalMaintenance	1024
Eas	CustomerExpectation	1024
Domt	InternalMaintenance	1024
Owa	InternalMaintenance	1024
TeamMailboxSync	CustomerExpectation	1024
Pop	InternalMaintenance	1024
Imap	InternalMaintenance	1024
Momt	InternalMaintenance	1024
Transport	CustomerExpectation	1024
TransportSync	InternalMaintenance	1024
OwaVoice	InternalMaintenance	1024
OrgContactsSyncAssistant	InternalMaintenance	1024
PublicFolderMailboxSync	CustomerExpectation	1024
InferenceDataCollectionAssistant	Discretionary	1
PeopleRelevanceAssistant	InternalMaintenance	1024
SiteMailboxAssistant	InternalMaintenance	1024
PushNotificationService	InternalMaintenance	1024
MailboxReplicationServiceHighPriority	Urgent	1024
StoreUrgentMaintenanceAssistant	Urgent	1024
StoreOnlineIntegrityCheckAssistant	InternalMaintenance	1024
StoreScheduledIntegrityCheckAssistant	Discretionary	1024
MailboxProcessorAssistant	CustomerExpectation	1024
E4eSender	InternalMaintenance	1024
E4eRecipient	InternalMaintenance	1024
MailboxAssociationReplicationAssistant	CustomerExpectation	1024
SharePointSignalStoreAssistant	InternalMaintenance	1024
PeopleCentricTriageAssistant	InternalMaintenance	1024
MailboxReplicationServiceInternalMai...	InternalMaintenance	1024
MailboxReplicationServiceInteractive	CustomerExpectation	1024
ProbeTimeBasedAssistant	CustomerExpectation	1024
DarRuntime	InternalMaintenance	1024
SearchIndexRepairTimebasedAssistant	InternalMaintenance	1024
DarTaskStoreTimeBasedAssistant	InternalMaintenance	1024
OutlookService	InternalMaintenance	1024
GroupMailboxAssistant	InternalMaintenance	1024
StoreDSMaintenanceAssistant	InternalMaintenance	1024
O365SuiteService	CustomerExpectation	1024

Enjoy!

Comments

• Anonymous
  January 30, 2015
  Thanks for sharing
• Anonymous
  November 03, 2015
  Great post Ben, I've been looking for something public with all of this explained!