Client Message Size Limits

Posted on June 29, 2015 by Michel de Rooij

Last Update: Version 1.4, July 19th, 2019

Exchange Server 2013 and Exchange Server 2016 enforces certain message size limits when it comes to client messages. These limits are in-place so clients can’t generate excessive load on your Exchange environment. These limits are determined for various access methods in multiple web.config files on Exchange Client Access Servers as well as Mailbox Servers.

Sometimes you may have good reasons to increase those limits. For example, when migrating to Office 365 using a product like MigrationWiz, you may want to increase the limit for Exchange Web Service (EWS) requests to allow for migration of larger items. Another example is when you want to allow for bigger attachments in Outlook WebApp (OWA). On TechNet, there’s an article on how to reconfigure these limits. However, the process consists of editing multiple web.config files, replacing multiple values in the same file, and following this process on each Exchange 2013/2016 server in your environment. This is not only labor intensive and prone to error, but becomes tedious when you consider that each Cumulative Update will overwrite your web.config files.

But do not despair. To execute these changes for OWA and EWS, I have created a PowerShell script which will perform these tasks for you.

Requirements
Using the script requires Exchange 2013. You need to provide the server name (default is local server) or AllServers to apply to all Exchange 2013/2016 servers in your environment. The script will modify the web.config remotely using the system share (e.g. C$), using the location of the Exchange installation, and uses IISRESET tool to restart IIS. It will create a backup of the web.config before modifying it.

Notes:

The script checks for running in elevated administrator mode when running against the local machine.
Current version of the script requires Exchange Management Shell, to run Exchange cmdlets for checking installed roles a.o., as the web.config files which require editing depend on the installed roles.
For OWA, add ~33% to the value you want to specify to compensate for encoding overhead.
When connected to an Exchange server, the script processes the server hosting the EMS session last to prevent abortion caused by IIS reset.
Script currently runs against Exchange 2013 or Exchange 2016.

Usage
The script Configure-ClientSizeLimits.ps1 uses the following syntax:

.\Configure-ClientSizeLimits.ps1 [-Server |-AllServers] [-OWA <size>] [-EWS <size>] [-EAS <size>] [-Reset] [-NoBackup]

A quick walk-through on the parameters and switches:

Server specifies the server to configure. When omitted, it will configure the local server. This parameter is mutually exclusive with AllServers.
AllServers switch specifies to configure all Exchange 2013 servers. This switch is mutually exclusive with Server.
OWA configures the message size limit for Outlook Web Access. Value is in bytes.
EWS configures the message size limit for Exchange Web Services. Value is in bytes.
EAS configures the message size limit for Exchange ActiveSync. Value is in bytes.
NoBackup tells the script not to make backup copies of modified web.config files.
Reset switch specifies to perform an IISRESET against servers after reconfiguration of client-specific message size limits.

So, suppose you want to configure OWA, EWS and EAS client message size limits on the local Exchange server, you can use:

.\Configure-ClientSizeLimits.ps1 -OWA 15MB -EWS 15MB EAS 15MB

If you want to configure EWS limits for all servers, resetting IIS, you could use:

.\Configure-ClientSizeLimits.ps1 -AllServers -EWS 10240 -Reset

Download
You can download the script from the TechNet Gallery here or GitHub.

Feedback
Feedback is welcomed through the comments. If you got scripting suggestions or questions, do not hesitate using the contact form.

Revision
See TechNet Gallery page.

Exchange 2013 Server Role Requirements Calculator 7.6

Posted on June 23, 2015 by Michel de Rooij

The Exchange team published an update for the Exchange 2013 Server Role Requirements Calculator as well. The new version number is 7.6.

Changes since version 6.6:

Added support for ReplayLagManager
Added support for PreferredMaximumActiveDatabases
Added new table that exposes theoretical CPU utilization for each mode (normal runtime, first server failure, second server failure, site failure, site failure + 1 failure)
Added Restore-DatabaseAvailabilityGroup scenario support in Distribution algorithm
Added warning about designs that include more than24 processor cores / server and 96GB of memory
Added support for DAGs without Administrative Access Point (default behavior is no administrative access point) in the CreateDAG script
Changed default for Deleted Item Retention in export file to be the highest profile value for Deleted Item Retention
Changed default for Circular Logging in export file to be true when using Exchange Native Protection
Added ability to save scripts and CSV files to OneDrive for Business
Fixed CreateDAG.ps1 script error for DAG creation without administrative IP address
Modified CreateMBDatabases.ps1 to ignore CircularLogging choice and modified CreateMBDatabaseCopies.ps1 to enforce CircularLogging choice
Fixed Export DAG list function to use the correct value for MaximumActiveDatabases
Added support for MaximumPreferredActiveDatabases and AutoDatabaseMountDial in Export DAG List function and createdag.ps1
Modified CreateMBDatabaseCopies.ps1 to remove sleep timer, improving copy creation significantly
Fixed createdag.ps1 to not generate an error when there is no alternate witness server provided

Fixes since version 6.6:

Fixed an issue that prevented the calculator from displaying results when site resilience was disabled while Active/Active (Single DAG) was selected
Changed Processor Cores/Server to not use a list drop down, thereby enabling customers to enter in configurations they are deploying.
Fixed bugs in Diskpart script with PrepareAutoReseedVolume switch and WhatIf processing
Fixed bug in Diskpart with escaping quotes in some languages
Fixed bug with display of lag copies in single site design
Fixed multiple databases / volume calculation to take into account symmetric designs that utilize an odd number of servers in a single site
Fixed scenario to count number of servers in A/P scenario where the only copy deployed in DR is a lagged copy
Fixed #NAME error in Database Copy Configuration table for standalone configurations
Updated DC1 memory sizing to take into account site failure mode for A/A (Single DAG) designs involving a 2 copy architectures
Updated Distribution Tab error reporting and Lastrow calculation
Fixed copy count validation formula for site resilient scenarios to not allow more copies in the primary datacenter than the number of servers
Added support for 10TB and 12TB capacity disks
Fixed run-time error on distribution tab when disabling site resilience
Fixed distribution error when disabling cross-site failover
Fixed bug in Distribution tab ActiveServer formula when modeling Cross Site Failover behavior
Fixed an issue with the distribution tab throwing an error when two files were opened at the same time
Fixed distribution algorithm where lagged copies were not always represented correctly
Blocked unsupported A/A (Single DAG) scenario where copy count is not the same in both datacenters

You can download the calculator here. For more information, please consult the list of changes here or Read Me here.

Exchange 2013 Cumulative Update 9

Posted on June 23, 2015 by Michel de Rooij

The Exchange Team released Cumulative Update 9 for Exchange Server 2013 (KB3049849). This update raises Exchange 2013 version number to 15.0.1104.5.

Cumulative Update reintroduces configuration of sent items for shared mailboxes, as was possible in Exchange 2010 but wasn’t available in Exchange 2013 yet. More information here.

Next to a security fix for MS15-064, this Cumulative Update contains the following fixes:

KB2983216 Category setting on an item in Outlook jumps the selection to the top of the list in an Exchange Server 2013 environment
KB2988660 Role assignment with custom write scope fails in an Exchange Server 2013 environment
KB3003978 Email messages are displayed with incorrect format in Outlook in an Exchange Server 2013 environment
KB3006849 GSSAPI-based Kerberos authentication protocol is not offered to IMAP clients in Exchange Server 2013
KB3009631 Advanced Find against the Sent Items folder in Outlook returns no result in Exchange Server 2013
KB3032153 Recurring events in Calendar over DST are not adjusted on all ActiveSync devices in all Exchange Server environments
KB3040681 MapiExceptionTimeout error during a hierarchy synchronization process of multiple public folders in Exchange Server 2013
KB3040683 System WLM overrides do not work when you do on-premises installations in Exchange Server 2013
KB3049081 OwaDeepTestProbe probe fails intermittently on a server that installs the Mailbox server role in Exchange Server 2013
KB3049771 Outlook Web App logon page takes longer time than expected to time out in an Exchange Server 2013 environment
KB3050825 EdgeTransport.exe starts to crash when PriorityQueuingEnabled is set to “True” in Exchange Server 2013
KB3050877 Emails that are sent as a secondary mailbox are not saved in the delegate’s Sent Items folder in Exchange Server 2013
KB3055940 “Object reference not set to an instance” error when you install cumulative update in Exchange Server 2013
KB3056045 “Cannot find Template User object” error when you find contacts that use a consumer domain in Exchange Server 2013
KB3056133 Exchange Server 2013 Activation time of transport rule is not displayed in UTC time
KB3056413 SMTP connection fails when you log on with a child domain account and use NTLM authentication in Exchange Server 2013
KB3056817 Update adds the Let me select the message option in Outlook Web App in an Exchange Server 2013 environment
KB3056822 Dynamics CRM 2013 stops synchronizing items from mailbox in an Exchange Server 2013 environment
KB3060825 The MSExchangeDelivery service crashes when you receive an email message from a specific sender in Exchange Server 2013
KB3064393 “Bad Command. 12” error and IMAP CAPABILITY commands are not offered in an Exchange Server 2013 co-existence environment
KB3068681 RPC encryption requirement is re-enabled for RPC Client Access Service after you upgrade server in Exchange Server 2013
KB3069060 Recurring meetings are accepted when their time conflicts on the same room mailbox in Exchange Server 2013
KB3069501 Duplicate folders are created after a mailbox move in Exchange Server 2013 Enterprise
KB3071427 Outlook Web App still downloads web beacon contents when you forward email messages in Exchange Server 2013

Notes:

If the new Set-Mailbox parameters for Sent Items configuration, i.e. MessageCopyForSentAsEnabled and MessageCopyForSendOnBehalfEnabled, are not available after installing this CU, run Setup /PrepareAD /IAcceptExchangeServerLicenseTerms explicitly.
When using Exchange hybrid deployments or Exchange Online Archiving (EOA), you are required to stay current.
Previously released CU7 introduced changes to prevent restoration of pre-CU7 databases. Pre-CU7 users are advised to perform a full backup post-upgrade to CU7 or later.
Previously released CU7 added support for hierarchies containing 250,000 modern public folders. Consult this article for co-existence scenarios.

This Cumulative Update does not include schema or Active Directory changes when compared to Cumulative Update 7. If you have deployed a version earlier than CU7, make sure you run PrepareSchema /PrepareAD. If you want to speed up the Cumulative Update installation process, you can temporarily disable certificate revocation checking as described here.

Note that Cumulative Updates can be installed directly, i.e. no need to install RTM prior to installing Cumulative Updates. Note that once installed, you can’t uninstall a Cumulative Update nor any of the installed Exchange server roles. The order of upgrading servers is irrelevant, unlike with previous generations of Exchange.

Finally, and I can’t emphasize this enough: For any Hotfix, Rollup, Service Pack or Cumulative Update, I’d recommend to thoroughly test this in a test and acceptance environment first, prior to implementing it in production. When you lack such facilities, hold out a week or two and monitor the comments on the release article or TechNet forum for any issues.

You can download Exchange 2013 Cumulative Update 8 here; UM Language Packs can be found here.

Exchange 2010 SP3 RU10 & Exchange 2007 SP3 RU17

Posted on June 23, 2015 by Michel de Rooij

The Exchange Team released Rollup 10 for Exchange Server 2010 Service Pack 3 (KB3049853) as well as Rollup 17 for Exchange Server 2007 Service Pack 3 (KB3056710). These update raises the version numbers to 14.3.248.2 and 8.3.417.1 respectively.

Rollup 10 contains the following fixes for Exchange Server 2010 SP3:

KB 3069055 Various DAG maintenance scripts do not work in an Exchange Server 2010 environment
KB 3057422 “MapiExceptionNoAccess: Unable to query table rows” error and some mailboxes cannot be moved
KB 3056750 Exchange ActiveSync application pool crashes in an Exchange Server 2010 environment
KB 3054644 “The item no longer exists” error when you access an archive mailbox in Outlook Web App in Exchange Server 2010
KB 3051284 Event ID 4999 is logged and MSExchangeServicesAppPool crashes in an Exchange Server 2010 environment
KB 3049596 Event ID 4999 is logged and remote procedure call Client Access service crashes in an Exchange Server 2010 environment
KB 2964344 MSExchangeRPC service stops working intermittently in Exchange Server 2010
KB 3055764 Exchange Server 2010 Address Book Service crashes with event ID 4999

For Exchange Server 2007 SP3, the Rollup 17 contains the following fix:

KB 3057222 “InvaIidOperationException” error and cannot open digitally signed or NDR messages in FIPS-enabled Exchange Server 2007

Notes:

If you want to speed up the update process for systems without internet access, you can follow the procedure described here to disable publisher’s certificate revocation checking.
If you got an Exchange 2010 DAG, and want to properly update the DAG members, check the instructions here.

Rollups are cumulative per service pack level, i.e. they contain fixes released in earlier update Rollups for the same product level (RTM, SP). This means you don’t need to install previous Rollups during a fresh installation but can start with the latest Rollup package.

You can download Exchange 2010 SP3 Rollup 10 here and Exchange 2007 SP3 Rollup 14 here.

Exchange data: NTFS vs. ReFS

Posted on May 16, 2015 by Michel de Rooij

For Exchange, NTFS has been the file system of choice since time immemorial. In 2012, Windows Server 2012 introduced a new file system: Resilient File System or just ReFS. ReFS was designed to overcome some of the limitations of NTFS, in particular in the area of maintaining data integrity. More information on ReFS in comparison to NTFS can be found here.

At that time Windows Server 2012 went RTM, the latest version of Exchange, Exchange 2010, was not supported to run on ReFS. Present day, Exchange 2010 still doesn’t support ReFS. However, when Exchange 2013 entered the arena shortly after Windows Server 2012, it came with support for both NTFS and ReFS file systems. NTFS was still considered best practice, with ReFS being a supported option with the added recommendation to turn off ReFS’ integrity checking feature, and disabling it for Content Index-exclusive volume is optional. It may therefor come as no surprise that nearly all customers are deploying Exchange 2013 on NTFS volumes only.

That may change with Exchange 2016. As announced at Ignite 2015, for Exchange 2016 more emphasis will be put on following the Preferred Architecture design when deploying Exchange on-premises. The Exchange 2016 Preferred Architecture contains guidance to use ReFS formatted, BitLocker encrypted data volumes with Exchange 2016. The latter option is of course to protect organizations against theft of physical storage devices.

With some time to spare, I was interested to see what the impact would be on the storage performance when using NTFS or ReFS, and especially the performance penalty when enabling BitLocker on a volume. Similar to a comparison I did between Exchange 2010 and Exchange 2013 on different operating systems, I ran a JetStress 2013 test utilizing these 3 file systems to get a sense of what to expect.

The ESE engine files from Exchange 2013 CU8 were used for testing, along with the following parameters:

Mode	Test Disk Subsystem Throughput
Thread Count	12 (fixed)
Min/Max DB Cache	32 MB / 256 MB
Ins / Del / Repl / Read %	40/20/5/35
Lazy Commits	70%
Run Background DB Maintenance	True
Databases	1 x DB (186GB), 3 Copies
Running Time	2 Hours

Databases and logs were stored on a DAS SSD drive, and the volume was GPT partitioned with 64K allocation units. ReFS Integrity checking was disabled for the volume using:

Format-Volume –DriveLetter X -FileSystem ReFS -AllocationUnitSize 65536 -SetIntegrityStreams $false

The drive supported hardware encryption for BitLocker, which offloads encryption to the drive. You can verify that hardware encryption is used after enabling BitLocker on the volume by inspecting the BitLocker status using the manage-bde utility or Get-BitLockerVolume cmdlet:

As you can see from the EncryptionMethod property, this volume is protected using hardware-based BitLocker encryption. Perhaps needless to say, but the CPU performance penalty is substantial when using BitLocker with software encryption, and this mode is not to be used with I/O intensive applications like Exchange.

Note that if you deploy a Database Availability Group on ReFS formatted storage, and you want to use AutoReseed, you need to create or configure your DAG using the FileSystem parameter specifying ReFS, e.g.

New-DatabaseAvailabilityGroup -Name DAG1 -FileSystem ReFS

This makes sure that AutoReseed prepares volumes using the proper file system.

The results from the JetStress tests are show in the following table:

Test	NTFS	ReFS		ReFS+BitLocker
JetStress Version	15.0.658.4
ESE.DLL	15.0.1076.9
Operating System	6.2.9200.0
Overall Test Result	Passed	Passed		Passed
Achieved Transactional IOPS	1,613.13	1,407.55	-13%	1,379.98	-14%
Database Reads Average Latency (msec)	8.53	10.50	-23%	9.73	-14%
Database Writes Average Latency (msec)	12.80	20.80	-63%	19.98	-56%
Database Reads/sec	895.25	787.08	-12%	769.47	-14%
Database Writes/sec	726.48	628.55	-13%	618.65	-15%
Database Reads Average Bytes	35,220.22	35,375.26	0%	35,437.64	1%
Database Writes Average Bytes	34,389.82	34,510.95	0%	34,496.88	0%
Log Reads Average Latency (msec)	4.64	5.06	-9%	5.00	-8%
Log Writes Average Latency (msec)	5.16	7.22	-40%	6.73	-30%
Log Reads/sec	18.64	16.29	-13%	16.08	-14%
Log Writes/sec	87.25	72.81	-17%	73.82	-15%
Log Reads Average Bytes	232,562.72	232,562.01	0%	232,562.30	0%
Log Writes Average Bytes	25,005.97	26,210.03	5%	25,589.45	2%
Avg. % Processor Time	4.28	3.66	14%	3.60	16%

Some observations and notes:

ReFS caused a ~13-14% IOPS drop when compared to NTFS.
Using ReFS resulted in increased I/O latencies, especially write operations.
ReFS had a positive impact on the processor utilization, lowering average utilization by around 15%.
For some reason, average write latencies were lower using ReFS with BitLocker rather than without it (~10%).

Given the impact of file system choice on I/O performance and CPU utilization, I hope next versions of Exchange Server Role Calculator will feature an option to select which file system will be used to store Exchange data, as the difference in I/O performance and CPU utilization between NTFS and ReFS seems significant. Though this small test was performed with Exchange 2013 running on Windows Server 2012 R2, It could be that Exchange 2016 or the next version of Windows Server 2016 contain changes that will diminish the differences or perhaps even grant ReFS an advantage over NTFS. This is something we will only know after these products have shipped, something worth investigating later this year.

The JetStress reports can be found here.

I will finish with a short disclaimer: This test was only performed to get an indication of performance impact of using different file systems with Exchange 2013 utilizing identical hardware. The results are purely indicative, and not necessarily representative for other configurations nor meant to provide guidance or proof. Always test and validate your configuration using tools like JetStress before putting Exchange in production.