Private bytes used

The PercentagePrivateBytesUsed parameter is used to monitor the percentage of private bytes used by the EdgeTransport.exe process. The monitor is checking to make sure that the private bytes used does not exceed a default private bytes limit. For x64 computers, this limit is equal to 75% of the total physical RAM, or 1 terabyte (whichever is less).***

The EdgeTransport.exe process consumes memory as the queues fill. Check the queues to make sure that there are not any issues. If there are issues, troubleshoot the queues with the Exchange Mail Flow Analyzer (found in the Exchange Toolbox).

75%

73%

71%

Physical memory used

The PercentagePhysical MemoryUsedLimit parameter is used to monitor the total amount of memory in use by all processes.

Situations where the default High value is exceeded can be caused by queuing messages, which you probably want to troubleshoot. Often, the server attempts to reclaim memory by removing the least active messages from memory (dehydrating the queue). If this problem occurs frequently, consider removing roles from the server or re-evaluating your hardware (for example, add memory or add additional servers).

Dehydrating the queue means that unnecessary elements of queued messages are removed from cached memory, but still remain in the queue.

94%

89%

84%

Database disk space used

The intent of the PercentageDatabaseDiskSpaceUsed parameter is to monitor for available space for queued messages. This is done by monitoring the amount of used space in the database and comparing it to the amount of free space in the database and on the disk. This computation also takes into consideration the total disk size. The minimum free space is always 4GB in the release to manufacturing (RTM) version of Microsoft Exchange Server 2007 and 500MB with Microsoft Exchange 2007 SP1.

To prevent data loss, there are situations where Exchange may stop accepting mail. This may be caused by insufficient free disk resources. Check the queues for messages backing up. If the partition that holds the queue is too small, consider moving it to a drive with more space. Remove unnecessary files from the drive that holds the queue. In Exchange 2007 RTM, this issue occurs most frequently when the drive has less than 4 GB available.

In Exchange 2007 SP1, this issue occurs most frequently when the drive has less than 500 MB available. Requirements will be higher if the transport dumpster is enabled (if cluster continuous replication is used).

*

High value minus 2%

High value minus 4%

Amount of free hard disk drive space for message queue database transaction logs

The PercentageDatabase LoggingDiskSpaceUsed parameter monitors the amount of free space on the disk to make sure that the transaction logs always have enough room for committed transactions.

To prevent data loss, there are situations where Exchange may stop accepting mail. This may be caused by insufficient free disk resources If the queue database's transaction logs are on a different drive than the database, this issue indicates that the drive is too small.

**

High value minus 2%

High value minus 4%

Number of version buckets

Extensible Storage Engine (ESE) databases keep an in-memory list of modifications made to the database known as a Version Store. The VersionBuckets parameter keeps track of the number of different versions that are in memory because it is important that they are committed to disk. The size of allocated version buckets will fluctuate under normal conditions, but sizes can increase to unacceptable levels for various reasons, such as antivirus issues, problems with Jet integrity, large messages going through transport, and disk input/output (I/O) performance. If the size becomes too high, it could indicate that the Version Store has too many outstanding modifications that have yet to be committed.

Situations where the version buckets remain high are often transient and can generally be ignored. If the problem occurs frequently, it may be a good idea to verify that you have message size limits. If large messages are not the cause, consider monitoring the disk I/O performance counters to see if there is an underlying disk performance issue that could be causing the issue.

RTM: 100

SP1: 200

RTM: 60

SP1: 120

RTM:40

SP1: 80

Event Type: Warning

Event Source: MSExchangeTransport

Event Category: ResourceManager

Event ID: 15002

Description:

The resource pressure is constant at High. Statistics:

Queue database and disk space ("C:\Program Files\Microsoft\Exchange Server\TransportRoles\data\Queue\mail.que") = 54% [High] [Normal=45% MediumHigh=47% High=49%]

Queue database logging disk space ("C:\Program Files\Microsoft\Exchange Server\TransportRoles\data\Queue\") = 54% [Normal] [Normal=89% MediumHigh=91% High=93%]

Version buckets = 0 [Normal] [Normal=40 MediumHigh=60 High=100]

Private bytes = 10% [Normal] [Normal=71% MediumHigh=73% High=75%]

Physical memory load = 52% [limit is 94% to start dehydrating messages.]