Slow backups due to network performance


Validating network performance and possible impacts on backup speed.


Slow backup performance and system is not utilizing or you have ruled out inlineDedup or DedupNT?

For more detailed information on backup failures and performance issues see Unitrends KB 5062 - Backup Failures and Performance Issues


Investigate all aspects of the network between the Unitrends appliance and the client(s) being backed up.


Slow backups due to network performance issues may be caused by:

  • Excessive network hops. Unitrends recommends no more than 3 network hops between the Unitrends appliance and the client being backed up.  All links, including uplink/downlink and router interconnects should gigabit ethernet or faster.
  • Network link issues.  Try transferring a file from the client to the Unitrends samba share.  If it is slower than expected (for example, throughput of around 11 MB/s), validate all network links. Check for potential auto-negotiate issues on 100mbit links.
  • Firewall configuration. If possible, directly connect the Unitrends appliance to the subnet being backed up. Now test network throughput by starting a backup or copying a file to the samba share (it is recommended to test with an ISO image or other large file). If there is marked improvement in throughput, the firewall/router is likely contributing to the performance issues.  If not, check resources on both the Unitrends appliance and the client we are backing up.  Attempt to isolate the slow backup performance to one client or subnet.
This is not all inclusive, but rather a note on troubleshooting poor backup performance as it relates to network performance.

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