Data Protection Manager 2010 Slow / Inconsistent Replicas

I have an on site DPM 2010 Server, installed on Windows Server 2008 R2.

It backs up the following servers:
Hyper-V-1: Hyper-V Server on AMD Phenom II X6, 16GB Memory
Hyper-V-2: Hyper-V Server on AMD Phenom II X4, 16GB Memory
Server-1: Windows Server 2008 R2 on Intel Q8200, 4GB Memory

Server-1 and Hyper-V-2 back up as expected and in a timely fashion with DPM 2010. I have a full system bare-metal backup enabled for Server-1 and Child Partition Snapshots for Hyper-V Machines on Hyper-V-2.

However, when it comes to Hyper-V-1, Backup times are incredibly slow and fail because of this. I can back up small test files that are 10MB or less. These test files take about 20-30 min to back up and then fail with replica inconsistent. If I run a consistency check, they eventually acquire an "OK" protection status after another 1 or 2 20-30 min replica verification(s). Once working properly, these test files synchronize on schedule / properly as well.

With this slowness, a virtual machine child partition snapshot takes about 36 hours for initial replica creation. The replication fails as with the test files, however I have not been able to exclusively use the company network long enough to see if another 36 hour replica verification would work. Even though inconsistent replica is shown, in the details window under disk allocation, the correct size of the VM is shown as used so it at least copied over - though very slowly.

I also attempted manual replica creation. This also instantly gave me the replica inconsistent message and entered replica verification. I was not able to let that run for the 36 or so hours either to see a final result.

I do not believe Hyper-V-1 is overloaded. I have shut down all virtual machines and attempted the backup on just one running machine. I have also attempted it on a powered off machine.

I eventually got to the point where I re-formated the whole Hyper-V-1 hyper-V server and started from scratch. I then put the virtual machines back on the freshly installed server. Same results.

I have disabled any virus protection and firewalls on both the DPM server and Hyper-V-1 with no change as well.

Lastly, the DPM server has 2.7 TB of data storage, and is using less than half of that, so plenty of storage available.

I have been trying to figure this out for a couple weeks now. In the meantime I have just been manually backing up files onto a USB drive.

Thanks for any suggestions. I would be happy to hand over any log files / etc if that helps.

~ Ben



Who is Participating?
Rodney BarnhardtConnect With a Mentor Server AdministratorCommented:
Usually slowness or inconsistent replicas are caused by network issues. Below is a checklist of items:

The slowness could also be a memory leak as noted by several people having this problem:
amritaaromaAuthor Commented:
Thank you, rbarnhardt. I will review the information you have provided and let you know if anything helps out.


~ Ben
amritaaromaConnect With a Mentor Author Commented:
I have finally resolved this. After further research, my network card or network switch did not work with TCP Window Scaling. I disabled TCP Window Scaling for the particular Hyper-V server and replicas are created quickly and successfully.

Solution was found via the last post on:

More info on TCP Window Scaling:
amritaaromaAuthor Commented:
I have accepted my solution as an answer as well because it provides additional research and information that ultimately solved the issue.
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.