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Hyper-V Agent based Incremental/Differential Backups take just as long as the Full Backups to complete

Article: 100010038
Last Published: 2020-09-14
Ratings: 0 1
Product(s): Backup Exec

Problem

The Incremental/Differential backup for the Hyper-V Agent was introduced in Backup Exec 2012.  

Example:

Full Backup:

Backed up 6 files in 5 directories.
Processed 40,888,675,806 bytes in  1 hour,  59 minutes, and  2 seconds.
Throughput rate: 328 MB/min

Incremental:

Backed up 6 files in 5 directories.
Processed 4,618,477,752 bytes in  1 hour,  38 minutes, and  4 seconds.
Throughput rate: 44.9 MB/min

Cause

This behavior is because of the way Incremental/Differential backup is designed to work in Hyper-V environment.

Solution

The Incremental/Differential backup for the Hyper-V Agent was introduced in Backup Exec 2012. The Incremental/Differential backup method currently has the following benefits:

 
1.  Storage space is saved on the Backup Exec server. (Tape/Disk)
2.  The data transferred over the network is less.
 
The time taken on the Hyper-V host, to determine and calculate the changes made with respect to the previous backups will vary depending on amount of changes made to the virtual machines. Hence it is not necessary that there will also be a time gain upon running Incremental/Differential backups.  

Following recommendations can be tried to improve performance:

1. If Hyper-V host is running 2012 or later version, switch to VHDX files. They seem much faster. 

2. For Hyper-v host running 2012 or later version, enable Microsoft Incremental Backup Support.
 
The faster processing method: This method is faster than the standard processing method because it writes all changes to a new differencing disk that is backed up. Backup Exec supports only incremental backup using this method. To configure Hyper-V incremental and differential backup settings refer to the ' Configuring default backup settings'.
 

References

Etrack : 3249762 Etrack : 3269197

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