Storage Node load balancing

Storage Node:

Computer that manages physically attached storage devices or libraries, whose backup operations are administered from the controlling NetWorker server. Typically a “remote” storage node that resides on a host other than the NetWorker server.

NetWorker Performance Improvements: Save Session Distribution Overview

· Ability to configure and control load balancing across storage nodes

· Save session distribution options:

Max sessions:

» Save sessions are distributed on each storage node device’s max sessions attribute (default)

» More likely to concentrate the backup load on fewer storage nodes

Target sessions:

» Save sessions are distributed based on each storage nodes device’s target sessions attribute

» More likely to spread backup across multiple storage nodes

This can be applied to all NetWorker clients globally or to selected clients only. Save session distribution is not available for clone or recover operations.

When using the max sessions option (which is the default option) the NetWorker server first identifies the available storage node. Next it uses an available device on the first storage node that is working below its target session level. It continues to select devices until all devices are at their target level. Once all devices on the first storage node are at their target session level, it chooses to use the least loaded device that is running below its max session level. It will continue to use devices on the current node until all devices are at their max session level.

Once all devices on the current node are at their max session level, it will move onto the next available storage node and perform the same order of operations until all devices on that node are at their max session level. This process will continue until all devices on all storage nodes are running at their max session level.

When using the target sessions option the NetWorker server first identifies any available storage nodes. It then uses the first available device on the first storage node. It continues to choose devices on the first storage node until all devices on the first storage node are running at their target session level but below their max session level. NetWorker will choose to use a device on the next storage node once all of the devices on the first storage node are running at their target sessions. This occurs even if some of the devices are running below their max session level. This process continues until all of the available devices on all available storage nodes are running at their target session levels.

Once all of the devices are running at their target session levels it will run on the least loaded device that is below its max session level. Once the device has reached its max session level, it will move onto the next least loaded device. This process will occur until all eligible storage nodes are running at their max session levels.

The save session distribution can be changed from within the properties tab of the NetWorker server. The NetWorker console must be in diagnostic mode to change this value. This configuration can be overridden on a client basis within the client properties.

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About Ahmad Sabry ElGendi

https://www.linkedin.com/pub/ahmad-elgendi/94/223/559
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