Exchange Tip: Understanding Exchange 2003 Transaction-Log Purges
From the Exchange tips section at MSD2D.com
If a backup is proceeding successfully, Exchange Server 2003 will flush all logs that have been committed to the database. So, typically, all committed transaction logs will be flushed if
- all databases in the storage group (SG) are backed up.
- all databases in the SG are mounted during the backup.
The Information Store (IS) determines which logs will be deleted by looking at the first log that hasn't yet been committed and deleting all previous log files. You can view the first uncommitted transaction log by running the following Eseutil command against the checkpoint (.chk) file:
After the backup finishes, ESE Event ID 224 will be logged, specifying the series of transaction logs that will be deleted. For example, if the command
eseutil /mk E01.chk
outputs E010000G, E0000001 through E010000F will be deleted. The purging process is sequential and purges all log files in the series with one exception: The purge process will stop if it tries to delete a nonexistent log file. So, in the previous example, if log file E010000A is missing, only logs E0100005 through E0100009 will be deleted. In this scenario, after the next backup, Exchange will again try to purge all log files that have been committed. This time, the previous Eseutil command outputs E01000016 as the uncommitted log file; thus, E010000B through E0100015 will be purged.
If your transaction logs aren't being purged, sooner or later you'll run out of disk space. If you have to create space in a hurry, don't move the log files; compress them instead. (In my lab, I've seen 3GB worth of log files compress to 1.5GB.) For recovery scenarios and for the purge process to finish successfully, you shouldn't move the transaction logs.
For more information about Exchange 2003 transaction logging, see the Microsoft
articles "Exchange Transaction Logging in Exchange Server 2003" (http://www.microsoft.com/technet/prodtechnol/exchange/guides/UseE2k3RecStorGrps/d42ef86
0-170b-44fe-94c3-ec68e3b0e0ff.mspx), "XADM: Using Eseutil to Determine Which
Logs Have Been Committed" (http://support.microsoft.com/?kbid=182961),
and "How to remove Exchange Server transaction log files" (http://support.microsoft.com/?kbid=240145).
- Teo DeLasHeras
Performing a GAL Lookup from a Windows Mobile 5.0 Phone
How can I perform a Global Address List (GAL) lookup from a Windows Mobile 5.0 phone?
Unlike earlier versions of mobile devices, which could display only local contact information, Windows Mobile 5.0 devices that have the new Messaging & Security Feature Pack installed can query the Exchange Server 2003 GAL in a variety of ways. To use a Windows Mobile 5.0 device to find GAL-based contact information, perform these steps:
- From the Start menu, select the Contacts mobile applet.
- Select Find Online.
- Enter the name to search for, as Figure 1 shows, and click Find.
- From the displayed list of matches, select the desired contact.
To use the GAL when you send email messages in which either the To: or Cc:
box is selected, from the menu, click Add Recipient. On the Select a Contact
screen, select Find Online, then enter the user's name. From the resulting
list of matches, you can select the appropriate name.
- John Savill
Configuring Password Policies for Mobile Devices in Exchange 2003 SP2
How can I configure password requirements for mobile devices by using Exchange Server 2003 Service Pack 2 (SP2)?
The new Messaging & Security Feature Pack for Windows Mobile 5.0 lets you configure password policies from the Exchange server. To do so, follow these steps:
- Start Exchange System Manager (ESM) by clicking Start, Programs, Microsoft Exchange, System Manager.
- Expand Global Settings.
- Right-click Mobile Services and select Properties.
- Click Device Security.
- Select the Enforce password on device check box and configure the required options, such as minimum password length, character combinations, and the duration of inactivity that will lock the device. You can also choose how many failed attempts will result in wiping the device, how often to refresh, and whether to allow access to devices that don't support the password settings. Also, you can use the Exceptions button to set exceptions to the policy. Click OK.
- Click OK on the main Mobile Services dialog box.
The next time a device attempts to sync with the Exchange server, the mobile
device will display a message, as Figure 2
shows, and the user will need to accept the new password policy before gaining
further synchronization permission. After the user accepts the new password
policy, he or she must enter a new password to satisfy the new password policy,
as Figure 3 shows.
- John Savill
Get to Know the New Exchange Server Roles
At TechEd in June, Microsoft representatives spent a lot of time talking about Exchange Server 2007's cool new features. The company has posted a page of demos (http://www.microsoft.com/exchange/preview/evaluation/demos.mspx) that show off some of the new features in detail. If you haven't seen these demos, either live or on the Web, I encourage you to check them out to see some of what we have to look forward to in Exchange 2007 Beta 2.
A lot of misinformation is circulating about server roles in Exchange 2007, largely because Microsoft hasn't done a good job of answering the questions Exchange administrators are asking about the new roles. Microsoft's new FAQs at http://www.microsoft.com/exchange/preview/faq.mspx will help to a certain extent, but as a public service, I want to address some of the questions I've been hearing to help clarify what you need to know about the new server roles.
One question I often get is whether these roles can, must, or should coexist on a server. The Exchange 2007 server roles are modular, and you can install (or remove) them independently of one another. You can put four of the five roles (Mailbox, Hub Transport, Client Access, and Unified Messaging—UM) on a single server and dynamically add or remove any of these roles at any time. The remaining role, Edge Transport, must be installed on a separate server, but that's by design; remember that it's intended to reside in the perimeter network, while the other server roles should be restricted to the internal network.
That explanation leads to a related question: Is an Edge Transport server role a must? The answer, of course, is no. You get some additional security and message-hygiene features if you do use this role, but you can easily configure the Hub Transport server role to interchange messages with the Internet. As for the other roles, the Client Access, Mailbox, and Hub Transport roles are mandatory; you must have at least one of each in your Exchange organization. (Well, I guess you could get by with no Mailbox roles, but that wouldn't be a very useful setup!)
Exchange administrators who use clustering tend to ask lots of questions about Exchange 2007's cluster support. The Mailbox server role can be clustered, but the other roles can't. This setup makes perfect sense when you think about what those other roles do: They process transient data, and they all provide dynamic discovery tools so that clients and other roles can locate the currently available instances of a role. For example, if the Client Access server that your mailbox points to is down when you launch Microsoft Office Outlook 2007, the Outlook AutoConnect process (which runs when Outlook starts, when the
Client Access server or Mailbox server fails to respond after a given interval, and at an administrator-specified interval) will locate another available Client Access server and Mailbox server.
Speaking of clustering, with Cluster Continuous Replication (CCR), you can build a hot-site failover system based on a two-node cluster that has no single point of failure. Mailbox data can be replicated between cluster nodes so that the surviving node can seamlessly pick up operations if the primary node fails. By using this approach, you can realize a big improvement over Exchange 2003's clustering implementation.
What about scalability? At this point, that's a hard question to answer. The
only people who really know what kind of loads the new roles can handle are
at Microsoft, and they're not saying much. (The UM team, however, has said that
a UM server should be able to handle about 100 concurrent phone calls.) It's
premature to start making architectural decisions based on preliminary scalability
numbers or claims; as we get closer to product release, I expect to see better-defined
parameters for how to size servers to handle the various roles.
- Paul Robichauxs
GET MORE ONLINE
Follow these links to access the resources mentioned in this month's Exchange Ideas.
Exchange Tip: Understanding Exchange 2003 Transaction-Log Purges "Transaction Logs - Purging" tip posted at MDS2D.com http://msd2d.com/content/tip_viewitem_03noauth.aspx?id=9337f246-1eaa-447f-a213-a0b0b3a5facc§ion=exchange
Exchange FAQs Performing a GAL Lookup from a Windows Mobile 5.0 Phone "How do I perform a Global Address List (GAL) lookup from a Windows Mobile 5.0 phone?" John Savill's FAQ for Windows, InstantDoc ID 50627
Configuring Password Policies for Mobile Devices in Exchange 2003 SP2 "How do I configure password requirements for mobile devices by using Microsoft Exchange Server 2003 Service Pack 2 (SP2)?" John Savill's FAQ for Windows, InstantDoc ID 50625
Get to Know the New Exchange Server Roles "Exchange 2007 Server Roles and You," InstantDoc ID 53882