Database verification throttling
SnapManager allows you to throttle the database checksum verification rate with Exchange Server 2003 SP2 or later, or Exchange Server 2007. Database verification throttling enables you to manage your verification load.
- How database verification throttling works
Eseutil.exe, the Microsoft Exchange consistency checker utility, inserts a one-second pause after a given number of input output (I/O) operations during the database physical consistency verification. ChkSgFiles, the Microsoft Exchange integrity verification library, inserts a one-second pause after a given number of I/O operations during the database physical consistency verification.
- Database verification throttling options
SnapManager 5.0 and later for Microsoft Exchange supports two throttling options: Eseutil with Microsoft Exchange Server 2003, and ChkSgFiles with Microsoft Exchange Server 2007.
- Calculating the verification throttling sleep interval
You must calculate the appropriate sleep interval value to use for each server. Monitor the read and write performance of the LUNs on which the databases reside, and then calculate the verification throttle setting so that the average and peak physical disk performance is below the maximum values determined by Microsoft.
- Configuring database verification throttling
You have to configure database verification throttling on all of the Windows host systems that are to perform database verification and is running Exchange Server.
- Throttling entries in the SnapManager backup and verification report
If you enable either Eseutil throttling or ChkSgFiles throttling, the SnapManager Backup and verification report logs messages indicating that the throttling feature is enabled before each database verification operation.
- Verification override entry in the SnapManager restore report
You must restore only from verified database to ensure a successful restore operation. Before each database verification, the SnapManager restore report indicates if verification override is enabled. If the feature is enabled, the report includes the warning "Database verification before restore was overridden."
- Impact of database verification on performance
Database verification can impact the performance of both the Exchange server and the storage system. To overcome the performance impact, you can separate the database verification process and database backup operations.
