MSExchange.org Monthly Newsletter of May 2008 Sponsored by: Apptix

Welcome to the MSExchange.org newsletter by Henrik Walther, Exchange MVP, MCA: Messaging (Exchange Ranger) Apprentice, MCTS Windows Server 2008, MCITP Exchange 2007, MCSE 2003 Messaging/Security. Each month we will bring you interesting and helpful information on Exchange Server. We want to know what all *you* are interested in hearing about. Please send your suggestions for future newsletter content to: henrik@msexchange.org

1. Exchange 2007 Mailbox Servers: Storage Design Best Practices

Welcome to the May 2008 edition of the MSExchange.org newsletter!

This month I wanted to take the opportunity to talk about some of the best practice recommendations when it comes to how you should design the storage for an Exchange 2007 Mailbox server. As most of you are aware we can create up to 50 storage groups and 50 Mailbox databases on an Exchange 2007 Enterprise edition Mailbox server. Microsoft recommends creating one mailbox database per storage group. The reason is primarily because by doing so you reduce the impact caused in a disaster recovery situation, where log files in a storage group are lost. If you lose log files for a given storage group, this will affect all mailbox databases in that storage group. When dealing with cluster continuous replication-based Mailbox servers, you do not even have a choice, as you are blocked from creating more than one mailbox database per storage group in such a scenario.

Another best practice recommendation is to separate transaction log files from database files. There are a couple of reasons why this is so. First, having log files and databases placed on separate physical drives means that you will not lose both if a RAID group is lost. This makes a disaster recovery situation much more manageable. Second, because the read/write pattern for log files and ESE databases are very different, you will also improve performance considerably.

Depending on the number of mailboxes as well as the mailbox limits for the mailbox users, etc, you may need to create more than 24 LUNs on an Exchange 2007 Mailbox server. There is only a limited number of drive letters available in Windows Server 2003/2008. Because of the limited number of drive letters available, another best practice is to use a combination of drive letters and mount points. This way you could create 42 storage groups and databases by using 6 drive letters with 7 mount points on each database LUN.

In order to achieve the best performance possible on an Exchange 2007 server, you should partition database LUNs using RAID 10 or RAID 6. If the budget does not allow this, you could still use RAID 5. For the log file LUNs, you should use either RAID 10 or RAID 1. Also note that the read/write pattern for ESE databases is random. This means that nothing will hinder you from placing multiple databases on the same LUN as it will not matter significantly whether there is random read/write across one or multiple ESE databases. For example, Microsoft IT uses CCR-based Mailbox servers with 7 mailbox databases placed on each LUN.

The same is true for log files. Actually you can have log files for all databases. For example, 42 databases placed on a single LUN will not cause significant performance impacts. However bear in mind this depends a lot on the user profiles (IOPS per mailbox, etc) in your environment and what type of RAID is used for the LUNs.

Another tip is to always use dedicated storage for your Exchange Mailbox servers. Said in another way, you should never let the storage guys create your LUNs on RAID partitions used by other applications. This will have a huge performance impact and is difficult to troubleshoot!

Finally, remember that if you are planning to use a hardware-based VSS solution to back up your Exchange 2007 Mailbox servers, Microsoft recommends you use two LUNs per storage group – one for thedatabase and one for the log files. This means that a lot more LUNs will be required. For example, if you planned to create 42 storage groups and databases on a Mailbox server, you would need 80 LUNs! If you use traditional ESE streaming backup or a software-based VSS backup solution such as Data Protection Manager 2007 (DPM 2007), the recommendation is to create two LUNs per backup set (for example a LUN with 7 databases and a LUN with all associated log files).

There are a lot of other things to keep in mind when you design the storage layout for your Exchange 2007 Mailbox servers, so be sure to read the Mailbox Server Storage Design section in the Exchange 2007 Documentation on Microsoft TechNet.

Cheers,
Henrik Walther

Note:
Should you have any ideas for content in future editions of the MSExchange.org newsletter, you are more than welcome to shoot me an e-mail at Henrik@msexchange.org

2. Order Henrik Walther's Exchange Server 2007 book

3. MSExchange.org Learning Zone Articles and Videos of Interest

We have a great group of articles in the Learning Zone that will help you get a handle on your most difficult configuration issues. Here are just a few of the newer and more interesting articles:

• Managing Exchange 2003 with SCOM 2007 (Part 1)
• GroupWise to Exchange 2007 - Interoperability and Migration (Part 5)
• Moving from a Linux Mail Server and peer-to-peer network to Exchange Server 2007 (Part 3)
• Deploying an Exchange 2007 SP1 CCR Cluster on a Windows Server 2008 Failover Cluster – Part 3: Installing Exchange 2007 SP1 and Verifying CMS Functionality
• High Availability and Disaster Recovery for Exchange Servers - A Comparative Analysis
• Clustered Continuous Replication Failover with Standby Continuous Replication (Part 2)
• Continuous Backup for Exchange Server with DPM 2007 (Part 4)
• Moving from a Linux Mail Server and peer-to-peer network to Exchange Server 2007 (Part 2)

4. KB Articles of the Month

Here are some interesting and useful MSExchange related articles posted by Microsoft in the last month:

Exchange 2007

• The passive node computer account is unexpectedly assigned Full Control permissions after you install the Passive Clustered Mailbox role in an Exchange Server 2007 cluster environment
• Error message occurs when Outlook clients synchronize an offline address book with Exchange 2007: "0x80190193"
• If you try to connect a mobile device to a mailbox server through a server that is running  Exchange Server 2007, the mobile device may be unable to connect
• The OOF template may be delivered as an attachment in an Exchange 2007 environment when you use the "Reply with Template" option in Microsoft Outlook
• The address rewrite agent does not rewrite the address for Out of Office (OOF) messages in Exchange Server 2007
• A user may be unable to synchronize with an Exchange Server mailbox from a mobile device when a Client Access server has been upgraded to Exchange Server 2007 Service Pack 1
• Exchange Server 2007 does not have Transport Neutral Encapsulation Format (TNEF) capabilities for POP and IMAP protocols
• The MSExchangeSyncAppPool application pool crashes on a server that hosts an Exchange Server 2007 Client Access Server role
• When you try to migrate a mailbox from Exchange Server 2003 to Exchange Server 2007, the Exchange Management Shell may stop responding
• Failover takes a long time to finish in an Exchange Server 2007 cluster continuous replication environment
• When you try to run the Restore-mailbox cmdlet on a server that is running  Exchange Server 2007, you receive an error message
• A recipient sees unexpected text in the top of an e-mail message that you send in Exchange Server 2007
• If you run the "isinteg -dump" command against a dismounted store on a server that is running Exchange Server 2007, the Store.exe process stops unexpectedly
• Event ID 12011 is logged every time that the MSExchangeTransport service starts after you install Exchange Server 2007 Service Pack 1 on a computer that is running the German version of Windows Server 2003
• Exchange Server 2007 mailbox users cannot retrieve the free/busy information for Exchange Server 2003 mailbox users in a large Exchange Server organization that has more than 100 administrative groups
• You cannot log on to Outlook Web Access Light, and an error message occurs in Exchange Server 2007
• Error message after you apply Update Rollup 1 for Exchange Server 2007 Service Pack 1 in a Japanese environment: "Public Folder Management Console is not an allowed Snap-in"
• The EdgeTransport.exe process crashes intermittently, and event ID 1033 is logged in Exchange Server 2007
• Error message in Outlook when you click the signature icon of a signed e-mail message  that an Exchange Server 2007-based Edge server receives: "The digital signature is invalid"
• The Edgetransport.exe process may crash on an Edge server that is running Exchange Server 2007 Service Pack 1
• An exception occurs, and event IDs 4999 and 5000 are logged when you modify the Outlook Web Access user interface
• Error message occurs, and users cannot access the free/busy information after you use the Import-Mailbox cmdlet to import data to a mailbox in Exchange Server 2007 Service Pack 1
• After you install Exchange Server 2007 Service Pack 1, the Set-ExcecutionPolicy task causes an error message, and event ID 103 is logged
• Description of Update Rollup 2 for Exchange Server 2007 Service Pack 1
• The contents of .pst files are not imported into Exchange Server 2007 mailboxes when you use the Import-Mailbox cmdlet
• Mail flow to certain domains does not work when you run Exchange Server 2007 on a Windows Server 2008-based computer

Exchange 2003

• The Microsoft Exchange Information Store service stops responding when you move mailboxes on a server that is running  Exchange Server 2003
• Description of the updated IMailBoxStore::MoveMailbox method in Exchange 2000 Service Pack 3 or in Exchange 2003 Service Pack 2
• The Inetinfo.exe process crashes on an Exchange Server 2003 front-end server in certain configurations
• Error message when you enable the "Show in Groups" option for a folder that contains thousands of e-mail messages in Outlook: "Outlook is retrieving data from the Microsoft Exchange Server "
• The System Attendant resource cannot fail over in an Exchange Server 2003 cluster, and event IDs 1069, 1082 and, 1121 are logged
• Description of the March 2008 special daylight saving time (DST) update release of Exchange Server 2003 Service Pack 2
• Tasks are unexpectedly deleted even though they are not past their age limit in an Exchange Server 2003 environment
• The W3wp.exe process may crash frequently on Exchange Server 2003 servers in an organization that has many Outlook Web Access users

5. MSExchange News of the Month

• Cemaphore Issues First Beta Release of MailShadow for Google Apps
• Advanced Search now available on MSExchange.org
• White Paper: Outlook Anywhere Scalability with Outlook 2007, Outlook 2003, and Exchange 2007 
• Update Rollup 2 for Exchange Server 2007 Service Pack 1 Released
• MSExchange.org authors at the MVP Summit

6. Ask Henrik Walther a question

QUESTION:

Hi Henrik,

I see from all TechNet and other Microsoft articles that a standalone Mailbox server is a requirement for SCR – however, my Manager would like me to verify as to whether it is possible on a combined HTS/MB server?

I could not find any documentation to support this – I would greatly appreciate it if you would know the answer to this question.

ANSWER:

Yes both the SCR source as well as target Mailbox servers can hold additional roles such as the Hub Transport server role.

For more information about the requirements for SCR source and target servers see the following section in the Exchange 2007 Documentation on Microsoft TechNet.