Chapter 2: Capacity and Availability Management 31
7. Click Set after changing the Edit Attribute field for the attribute and then click OK.
8. Close the ADSI Edit tool by closing the MMC console application.
9. Wait for Active Directory replication to replicate this new value throughout the forest
(this might take some time—using ADSIEdit elsewhere in the organization will show
you how replication is proceeding).
10. Restart the Microsoft Exchange information store service on the Exchange 2000
computer.
Log Buffers
ESE uses a set of log buffers to hold information in memory before writing to the transac-
tion logs. For back-end servers, the default value is too low. This can cause excessive disk
I/Os to the transaction log drive. A significant performance improvement will be seen when
the server is under load or when users are sending large messages. The default value is 84;
this should be increased to 9,000 on all back-end servers.
The process for setting log buffers is very similar to increasing the store-database cache
size (as detailed earlier). You will need to use ADSI Edit to navigate to the storage group
object and then find the msExchESEParamLogBuffers attribute. The value is an integer
and it should be set manually to 9,000.
Tuning Active Directory IntegrationWhen there are numerous computers running Exchange 2000 in a Windows 2000 site, a
very large LDAP load can be put on the Active Directory servers. An Active Directory
server, by default, is configured to support a maximum of 20 active LDAP queries. If this
limit is reached, Active Directory will return the error LDAP_ADMIN_LIMIT_EXCEEDED
and will refuse to process further LDAP queries until the active number drops below 20.
Twenty is generally sufficient for most Active Directory servers, but it is necessary to increase
this value when you are running Exchange 2000 on six- or eight-processor servers, or if the
preceding error message is logged.
The maximum LDAP queries can be configured through the MaxActiveQueries attribute.
This can be adjusted using the NTDSUTIL.EXE tool. Increasing this setting will use a little
more memory in the LSASS.EXE process on the Active Directory server, so do not increase
this value any more than is necessary. The following steps show how you would increase
MaxActiveQueries to 40:
1. After opening the command prompt window, type NTDSUTIL.
2. Type LDAP POLICIES and press Enter.
3. Type CONNECTIONS and press Enter.
4. Type CONNECT TO SERVER <domain controller/Global Catalog server name> and
press Enter.
5. Type Q and press Enter.