Types of Errors

Robot Save considers errors to be operational or event.

Operational Errors

Operational errors represent a physical problem with a tape, such as being write-protected or having unexpired data on the tape. Operational errors can occur on any system, whether or not they’re in a data center.

Event Errors

Event errors represent a difference in the database between a system and the rest of the data center. These types of errors result when more than one system attempts to modify a database whose contents are shared across the data center. An event error also can occur if the communication between systems is down. Event errors can occur only in a multisystem data center environment. The following examples illustrate some of the situations that can result in an event error.

  • System A is in a restricted state and uses a volume 1. At the same (apparent) time, an operator uses volume 1 on another system in the data center. When the restricted-state system comes back up, an event error occurs because the same volume ID was used on two different systems.

  • On System A, the operator changes the number of volumes al- lowed in the container BIGBOX from 20 tapes to 30. At the same time on System B, another user changes the number of tapes allowed in BIGBOX to 40. This creates an error event for BIGBOX and you need to select which system has the value you want to use.

  • System A uses volume BB0006 from the scratch pool during a backup. At the same time, System B attaches volume BB0006 to a rotation. This creates an event error for the volume.

    • An event error can result any time you create, change, or delete the same item (from the following) on more than one system at the same time: Volumes, Media, Containers, Locations, Move Sets, or AMLs

  • System A creates location TOPSHELF as on-site. System B creates location TOPSHELF as off-site. The other systems in the data center would show TOPSHELF as either on-site or off-site, depending on which data reached the DCMS first.

    Note: Even if System B created the location as on-site, the error would still be created. The error doesn’t necessarily signify that the data is different, only that something happened to the same object on two different systems, each without knowing about each other's actions.

Robot Save treats operational and event errors differently. Operational errors are considered to be of “lesser” importance than are event errors, and are treated more as notifications of the error condition. For example, a tape that generates an operational error because it is write-protected still can be involved in volume movement or container changes.

Once an event error occurs, all other events for that object are considered part of the same error until the error condition no longer exists.