Microsoft Office Tutorials and References
In Depth Information
Setup and Configuration Considerations
When you set up Excel Services specifically for solutions that offload workbook calculations to the server,
you should revisit all the defaults settings and configure the server so that it is optimized for your scenario.
You probably need to adjust the following settings (among others):
Workbook size — The workbooks that you choose to be offloaded from the client to the server are
most likely larger than the 10MB default. The maximum size is 2,000MB.
Maximum Request Duration — You may want to adjust this to -1 so that sessions never timeout.
In addition to the Excel Services settings, you need to increase the timeout settings within IIS
(specifically, the settings for ASP.Net).
Volatile Function Cache Lifetime — You may want to turn off all caching features (set this value to
0) so that each calculation is guaranteed to represent the latest values. Based on the assumption
that workbook calculation takes a significant amount of time and there is no end-user wait time
for the browser page refresh, the potential gain from caching volatile functions is often outweighed
by keeping the values current according to the calculation of the workbook.
Session timeout — Either increase the timeout or adjust this to -1 so that sessions never timeout.
Workbook Calculation Mode — You can override the Calculation mode in the workbook and set
this to manual. This is relevant if your solution requires setting multiple parameters or updating
external data before calculating the workbook. If the workbook is saved with automatic
calculation, you incur the calculation cost for each parameter set.
External Data Cache Lifetime — For workbooks that include external data, you should consider
changing this to 0.
Maximum Sessions Per User — If your application is running all workbook calculation requests
as the same user, consider raising the value on this setting.
Maximum Private Bytes — If you have a dedicated server or servers for workbook calculation,
you can increase the amount of memory they use by changing this setting to something higher
than 50 percent of the physical memory (the default).
Caching — You can adjust all workbook cache settings to disable caching altogether if your
system will always be iterating through new workbooks being submitted. This frees up the
memory for the active workbooks. You need to disable both the unused items cache (represented by
the Caching of Unused Files setting) and the Maximum Size of Workbook Cache size setting.
To adjust these settings, you need to have administrative permissions to Excel Services. Chapter 7
discusses where and how to change these settings.
Deployment Topology Considerations
From a deployment perspective, to achieve the best performance and robustness, you should isolate the
Excel Services boxes as an entirely separate farm. If you have an Office Server farm that you are using
to support your solution, consider breaking out the Excel Calculation Services (ECS) boxes to dedicated
hardware. In addition, consider locking down the access to this farm or to the Excel Services
functionality to prevent usage of other features from affecting the server performance and reliability.