NetVault SmartDisk 11.4.5 - Installation Guide

Deduplicated restore process

Garbage Collection process

When backups targeted to NetVault SmartDisk are retired, the data is removed from the backup database; however, the unique Chunks are not automatically removed from the Chunk Store. The NetVault SmartDisk Garbage Collection process is designed to remove orphaned Chunks from the Chunk Store and reclaim disk space. To do so, Garbage Collection maintains reference counts of added and deleted Chunks, and it deletes or rewrites partially used Chunk pages.

Garbage Collection cannot run at the same time as deduplication, because deduplication must write to the Chunk Store. During the configured Garbage Collection window, data waiting for deduplication is queued until Garbage Collection has completed. By default, the Garbage Collection window is from 18:00 through 06:00 every night. Because Garbage Collection has less impact on the speed at which new backups are staged than deduplication does, Quest recommends that you update the Garbage Collection windows to ensure that they match your backup windows. Outside the Garbage Collection window, Garbage Collection is only started if no data is being deduplicated or is queued for deduplication. If data becomes available for deduplication outside the Garbage Collection window and Garbage Collection is active, Garbage Collection is stopped and deduplication proceeds. For more information about scheduling Garbage Collection, see the Quest NetVault SmartDisk Administrator's Guide.

Quest also recommends scheduling regular Garbage Collection to avoid delays associated with collecting large amounts of data.

NOTE: If a backup job that uses deduplication is canceled, the Chunk Store space used by segments that have already been deduplicated is not reclaimed until the next Garbage Collection occurs. Space used by the Staging Store and license enforcement is reclaimed immediately.

Planning your NetVault SmartDisk deployment

Deployment strategy: an overview

A NetVault SmartDisk deployment strategy includes multiple components, which you define before installing NetVault SmartDisk. To ensure a successful deployment, complete the following steps, which are described in detail in subsequent sections:

NetVault Backup is used as an example throughout this section; however, you can use any product that works with NetVault SmartDisk.

IMPORTANT: While planning deployment of NetVault SmartDisk, you must deploy it on physical devices and you must use different paths for Staging and Store to ensure that load balancing is maintained. You cannot deploy NetVault SmartDisk on virtual machines. Also, if you intend to use deduplication, NetVault SmartDisk must reside on a dedicated NetVault SmartDisk machine; you cannot install it on the backup server or client.

Before calculating the required NetVault SmartDisk Capacity, ensure that the backups being targeted to NetVault SmartDisk are compatible with NetVault SmartDisk. For more information, see the Quest NetVault Backup Compatibility Guide.