Slow Disk-to-Disk backups? It might be a simple fix!

by | Sep 25, 2017 | Infrastructure | 0 comments

If you are conducting disk-to-disk backups and you feel like your performance is subpar, there are a few places to check for a bottleneck or slowness in the environment.  In this blog I will discuss a few areas I like to start with when trying to troubleshoot slow disk-to-disk backups.  I am going to start with some of the more common items to check, and then move on to some that may be a bit less obvious if those don’t resolve the issue.

Disk Speed

The first place I would suggest checking is, of course, the underlying storage.  Because of the vast amounts of different storage infrastructure, troubleshooting that can be an entire project in and of itself and is beyond the scope of this blog; I recommend working with the manufacturer. If you have proven the disk speed is not the issue, there are a few other places to check next.

Network Speed

After checking the disks, I like to use a simple utility to verify network speeds between my backup client and server.  Assuming both devices are Windows, you can use a tool called NTttcp.exe:

Simply run this utility on the backup server and the backup client, repeating the test in both directions, to test your raw network speed. Not the issue?  Let’s move on to another possibility.


Consider enabling software compression to help improve performance.  For Veritas Backup Exec, software compression happens at the agent.  This means if your network connection between the server and the client is a 1000mb Ethernet connection, you can effectively increase that bandwidth based on your compression ratio.  For example, if you are getting a 1.3:1 compression ratio, you’ve effectively just turned your 1000mb Ethernet connection into a 1300mb Ethernet connection for free!

Even if you’re not filling your entire network pipe, by compressing the data at the source, it means you’re transmitting less and, in turn, waiting for less acknowledgements for the data being transmitted.  This in itself can help speed things up, even if your network itself is not specifically bottlenecking the data transfer.  Try it out – you have nothing to lose.


Another piece that people forget about is the antivirus software.  Antivirus software will try to scan the backup to disk files as they are being written.  This can drastically slow performance!  Consider enabling exclusions in your antivirus client and exclude your backup to disk directories.

These are just a few places to start to troubleshoot slow performance when backing up to disk.  If you’re having issues with your backups and need help troubleshooting, upgrading, or engineering a new solution, such as cloud based backups, send us an email to  We are happy to help!