When you take a snapshot of server objects, information may be stored in two possible locations.
When you take a snapshot of most types of server objects, only attribute information is saved, such as the name of a patch, its version, and the date of installation. Attribute information is saved in the database. Snapshots of file system content are stored on the file server.
While a Snapshot Job is running, the system temporarily generates files on your application server machine. These files are removed when the job run completes. Your application server machine should have sufficient disk space to accommodate temporary files. The amount of space required varies depending on the complexity of the objects included in a snapshot. In most cases, the amount of space BMC recommends for a BMC Server Automation Console is sufficient. (See System requirements.) However, if the Application Server's default configuration has been modified to process more work items simultaneously, your local machine may require additional disk space for processing snapshots. Contact http://www.bmc.com/support for recommendations on disk space requirements.
A Snapshot Job consists of two categories of information:
- Job definition — Information such as the job description, schedule, and list of targeted servers.
- Server object information — Attributes of the server objects included in the snapshot. These server objects are specified by selecting a component template to use as the basis of a snapshot or manually choosing server objects when you define the Snapshot Job.
Both types of information are stored in the BMC Server Automation system database.
The first time you run a Snapshot Job, it collects attribute information for all server objects specified in the component template or the server-object based job definition. This initial set of data is known as a baseline. If no changes are made to either the job definition or the component template associated with the job, subsequent runs of the job only collect server object attributes that have changed since the last time the job was run.
The BMC Server Automation system maintains Snapshot Jobs and their associated component templates as versioned objects. If you make a change to either of these objects between runs of a Snapshot Job, the versions increment and the next run of the Snapshot Job stores new values in the database for each server object collected by the job, regardless of whether the values have changed since the last job run. This is known as rebaselining the snapshot.
Any change to a Snapshot Job or its associated component template triggers rebaselining. For example, any changes to the job's description, schedule, list of target servers, associated properties, or permissions (ACL specifications) causes rebaselining. If you modify a server object-based Snapshot Job definition by adding, removing, or modifying parts, rebaselining occurs. Similarly, if you modify a component template associated with a Snapshot Job in any way, rebaselining occurs. In short, any change to a Snapshot Job definition or a related component template triggers rebaselining.