Parallelism - This attribute in the Server resource sets the maximum number of savestreams that Backup allows to arrive at the server at one time. The maximum parallelism value is determined by the version of Backup you purchased. Target Sessions - This attribute in the Devices resource sets the number of save streams that a storage device can manage and multiplex to a volume. Use this attribute to maximize the performance of each device.

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You can increase backup speed by setting Backup to multiplex (or interleaf) data on a storage device. That is, data from more than one save set can be written to a single storage volume, and data from one save set can be spread acr oss multiple volumes. (Each save set that is multiplexed must, by definition, belong to the same pool of storage volumes.) Multiplexing optimizes and distributes the flow of data from multiple clients to all the storage devices that are available to Backup. At recover time, performance can suffer because the data from one save set may have been written to several volumes.
Backup maintains the integrity of each save set's data through a function that codes and tracks data by a save set identification number(ssid). The extent of multiplexing that can occur on any storage device is defined by the device's value for Target Sessions.
It is often more efficient for Backup to multiplex multiple save sets to the same volume than to write each save set to a separate device. For this reason, Backup attempts to assign to each device a number of save sets up to the target value of sessions before assigning a save set to the next device.

Event Notification

Backup reports activity and status to the system administrator through several different programs and interfaces. Backup uses notificationsto determine which events to report and how to report on those events.

Preconfigured Notifications

Backup includes many preconfigured notifications, which define the response of Backup to specific Backup events. The preconfigured notifications are described in "Notifications Resource" on page 23. You can edit the preconfigured notifications and create your own custom notifications. By selecting Details from the View menu in the nwadminGUI, or Display Options from the Options menu, then Hidden, in the nsradmininterface.

Chapter 3

Server and Storage Node Operations

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