Capacity Management - Office Web Application Service limits

Limit	Maximum value	Limit type	Notes
Cache size	100 GB	Threshold	Space available to render documents, created as part of a content database. By default, the cache available to render documents is 100 GB. We do not recommend that you increase the available cache.
Renders	One per document per second per CPU core per application server (maximum eight cores)	Boundary	This is the measured average number of renders that can be performed of "typical" documents on the application server over a period of time.

Capacity Management - SharePoint Web Analytics service limits

Limit	Maximum value	Limit type	Notes
SharePoint entities	30,000 per farm when Web Analytics is enabled	Supported	Do not enable Web Analytics if your farm contains, or is expected to contain, more than 30,000 SharePoint entities, which include all Web applications, site collections, and sites. This number is not exact, because different combinations of SharePoint entities might have a greater or lesser effect on farm performance than the tested scenario,  However, as the number of SharePoint entities in your farm closely approaches this limit, farm performance might fall to unacceptable levels.

Powershell command to Turn off the session state service on the farm

Disable-SPSessionStateService [-AssignmentCollection <SPAssignmentCollection>] [-Confirm [<SwitchParameter>]] [-WhatIf [<SwitchParameter>]]

Detailed Description
The Disable-SPSessionStateService cmdlet turns off the session state service. If your farm does not depend on session state service, we recommend that you disable it.

Note: 
When session state is disabled, some Microsoft SharePoint Server 2010 services, components, and third-party components no longer function. Changing this property modifies the Web.config file on every content Web application on every server in the farm.