Sharepoint 2010 Recycle Bin configuration

Sharepoint 2010 Web Applications make use of a second-stage recycle bin. This recycle bin is  configurated at Web Application level. When creating a new Web Application, the recycle bin functionality is activated by default with the following settings:
 

Recycle Bin Status:                         On
Delete Items in the Recycle Bin        After 30 days
Second Stage Recycle Bin               Add 50% of lice site quota
 

This configuration can be obtained from:
Central Administration > Manage Web Applicatons > [WebApp] > General Settings > General Settings. Scroll down to the Recycle Bin settings

How it works:

When a user deletes content, this content is moved to the first-stage Recycle Bin where it  can be restored by the user.  When the user empties the recycle bin or the retenetion period has been expired, the content will be moved to the second-stage recycle bin.
Once content resided in the second-stage recycle bin, it can only be restored by an Administrator. The content will stay in here until it is deleted by an Administrator or it is deleted by a timejob when the retention period has expired (30 days default). 

Second-stage Recycle Bin considerations

 
Take note of the storage aspect when configuring the second-stage recycle bin. By default, the second-stage Recycle Bin is on, and SharePoint limits the second-stage Recycle Bin size to 50 percent of the storage limit quota for the site collection. However, by default, new site collections have no quota applied, which effectively means that the second-stage Recycle Bin size is also unlimited.

Create site collection quotas to prevent this, or disable the second-stage recycle bin to prevent storage problems.

Note that: 

• Second-stage recycle bin does not count towards the site collection quota 
• First-stage recycle bin does count towards the site collection quota 
• Disabling Recycle bin even for a minute will immediately flush all the data from both recycle bins and those contents are unrecoverable.
• Disabling Recycle in at the web application level will still show the “Recycle Bin” link on all the pages but it wouldn’t hold any information to restore at the site or site collection level.