Users Guide

To reduce the I/O load created by Checksum Verification, you can add a 1-second delay after a specified number of I/Os.
You add the delay by specifying a registry key value as follows:
[HKEY_LOCAL_MACHINE\SOFTWARE\EqualLogic\ASM\Settings]
"EseutilThrottle"=dword:00001000
For example, if you specify a registry value of 1000, it results in a 1-second sleep after every 1000 Checksum Verification I/Os.
The range for this value is 100 to 100000.
Recovery Considerations for Exchange
● ASM/ME does not allow torn Smart Copies. A scheduled task fails when it results in a torn Exchange Smart Copy. See Torn
Smart Copies for an explanation of torn Smart Copies.
● ASM/ME prevents you from creating a multiple writer Smart Copy sets where the Exchange Writer and the SQL server are
included in a Smart Copy set. This condition is detected whether you create the Smart Copy from a volume, an application,
or a collection. ASM/ME also detects multiple writer Smart Copy sets when you attempt to create schedules for such
objects. If a multiple writer schedule runs, a warning is included in the notification email. It is possible to create an invalid
(multiple writer) configuration after a schedule was created. If you create an invalid configuration, the schedule fails when it
runs.
● When you create a Smart Copy set that contains multiple Exchange components from the same writer, ASM/ME displays a
warning but allows the operation to proceed. Dell recommends that you always configure your mailbox databases (for
Exchange 2016 and 2019) on separate volumes. This configuration ensures that if you do need to restore data, you will
restore only the damaged component. If you configure multiple Exchange mailbox databases on a single volume, all databases
are restored even if only one database was damaged.
● When you use Exchange utilities to relocate mailbox database components, and you have a Smart Copy that predates the
change, you cannot use that Smart Copy to recover data. Instead, use a Recovery mailbox database (for Exchange 2016 and
2019) created from that Smart Copy.
Checksum Verification and Soft Recovery
For Smart Copies of Exchange components, you should perform Checksum Verification to ensure data integrity.
Checksum Verification verifies the integrity of all files in the Smart Copy by using page Checksum Verification. Soft Recovery
configures the Smart Copy to replay the transaction logs to put the databases into a clean shutdown state.
When you create a Smart Copy, you can run Checksum Verification and Soft Recovery as follows:
● During Smart Copy creation—Run the operations while the Smart Copy is being created.
● After Smart Copy creation—Run the operations after you have created a Smart Copy. If you are running on a cluster, the
node must own the cluster resources. If the operation completes successfully, then this option is disabled the next time the
window opens.
● As part of a scheduled Global Verification task—If you are running on a cluster, the node must own cluster resources
required at the time that it selects a Smart Copy targeted for global verification to be processed.
● On a remote host—Run the operation as part of the Global Verification task on a remote verification server.
When a scheduled Global Verification task operation executes, ASM/ME updates the Smart Copy node to show that Checksum
Verification and Soft Recovery are in progress. A soon as the operation is complete, ASM/ME updates the Smart Copy node to
show the result.
If you notice I/O performance problems when running checksum verification, consider changing the eseutil.exe registry key
value. This procedure is defined in Microsoft Exchange eseutil.exe Utility.
If the Smart Copy is a replica of an Exchange component, rather than a snapshot or clone, the Checksum Verification and Soft
Recovery procedure is different. Volume replication is a continuous process and ASM/ME provides options to perform
Checksum Verification and Soft Recovery without disrupting replication.
For Exchange replicas only, the option to perform Checksum Verification is not available immediately after you create a Smart
Copy. See Checksum Verification and Soft Recovery for Replicas for more information.
Using ASM/ME with Exchange
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