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NetVault SmartDisk 11.4.5 - Administration Guide

Introducing NetVault SmartDisk Integrating NetVault SmartDisk with your backup product Using the command-line interface (CLI) Configuring NetVault SmartDisk Monitoring performance Troubleshooting

Calculating the reduction in the storage footprint

The NetVault SmartDisk Deduplication Option reduces the storage footprint required to store the protected data. To calculate the reduction in the storage footprint that NetVault SmartDisk is providing for protected data, use the following calculation:

Monitoring activity on configured volumes

You can check the current activity level for volumes that are currently configured for use with NetVault SmartDisk. For example, you might check the activity to understand why NetVault SmartDisk is not processing data that you believe is ready for deduplication. By monitoring the current activity, you can determine whether a significant number of backups are being written to the volume, which delays deduplication activity. Data remains queued for deduplication, and then begins after backup activity is reduced.

To check the activity level, view NetVault SmartDisk statistics by using either the config --show command and option — for more information, see Using the config command options — or by using the http://<localhost>:<port#>/proc/diskmanager/diskstorage/stats.stnz command in your web browser.

In the output that is displayed, review the information in the [SmartDisk:Volume] section to determine the level of activity.

For example:

The Active Operations value shows the number of NetVault SmartDisk disk-access operations occurring on the applicable volume. In the preceding example, there are four active operations on the Staging volume, /usr/smartdisk/diskmanager/stage, and the Deduplication Activity Cap is set to 4. This means that deduplication of data staged on this volume starts when the number of active operations on that volume is fewer than four.

The Deduplication Activity Cap minimizes the amount of disk thrashing that occurs when performing simultaneous access activities of the Staging volume. If deduplication of staged data is not taking place on a NetVault SmartDisk Instance during the deduplication window, you can check the Deduplication Activity Cap and Active Operations information for each configured Staging volume to determine if activity is preventing deduplication. If so, you might want to adjust the backup or deduplication window to eliminate overlaps.

You can set an activity cap for a volume by using the --dedupe-cap option with the config --add|--update --volume <path> command. For more information, see Extending NetVault SmartDisk Storage Pools.

Troubleshooting

Managing trace files

Because system performance can be affected when either the number of trace files in a directory or the combined size of trace files becomes significant, you can configure trace management and circular tracing to control these issues. NetVault SmartDisk includes two features for managing trace files, both of which are enabled by default:

resourcemanager: This process manages the combined number and size of all trace files by periodically deleting inactive files. It runs as a persistent, “start-of-day” process, along with others such as logd and superserver.
Circular tracing: This feature lets you control the number and size of trace files generated by NetVault SmartDisk processes.
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