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timb551Flag for United Kingdom of Great Britain and Northern Ireland

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Really slow DFS replication


I have two Server 2008 servers connected via a VPN.

I have DFSR setup to replicate one folder.

The replication seems to be extremely slow, so much so that its not catching up with itself so is constantly out of date.

I have already tried resetting it all up and it seemed to start replicating ok bt then slowed again.

I have noticed that on the 2nd server the size of the DFSR private folder in system volume information is large (17GB) but im not sure if i should worry about it.

Thanks in advance.

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Nagendra Pratap Singh
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how fast is your VPN?

If it is VPN, it can be slow.
Use oocla's mini ( after you test the available bandwidth at each location.

Set it up on each server and then test the transfer speed via the VPN.

DFS-R has a bandwidth setting, depending on what else is going through the VPN, you may have other higher priority traffic going through the VPN.
In a simple VPN you have 4 speeds.

Point A download
Point A upload
Point B download
Point B upload

Your VPN will work at the slowest speed of the above.  Often there would be some numbers but it is the CIR that is guaranteed by your ISP.
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The lines at each site are

Site A (Main Site): 17MB down, 1.5MB up
Site B (DR Site): 200MB down, 200MB up

I have run DFSR on slower networks than this and been ok.

DFSR is set to do unlimited on the bandwidth settings.

Whats the best way to test the speed between the two servers?
Ookla's mini from

It uses flash based testing.  Once unzipped, in IIS use the asp, aspx.

From Main site to DR the 1.5MBs is the limit on the speed, you should make sure that differential compression is selected.
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Differential compression is set.  I will try the mini software now
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Site A download from Site B : 9MB
Site B download from Site A : 1MB

That seems to make sense.
Your replication flow is from site A to site B.  Main site sees most of the changes and pushes it to DR. (Upstream bandwidth is the limit on replication)
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That's correct.
How large are the hourly changes?
What files do you have are these documents or are these larger CAD type files, where each file can be in the >100MB file?
Presumably the DFS does not include backup files.

Increasing the connection at sitea is the only possible solution given reducing the daily file addition/change is impractical.
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There is 1 x 300mb file daily and the rest are just word excel etc. Nothing major.

But at the moment its so far behind it could be approx. 50gb behind.

Should I get a full copy of site a copied directly to site b so that its up to date and then see what happens?
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Thanks Arnold.

How do you force the users to only use the local dfs share?

The dr bandwidth is unlimited and un capped.

The DR is part of a multi backup system so no worries there.

I will make the other changes you mentioned and see if it helps.
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