Network Latency Using Robocopy through VPN

[James Hancock]

I've been using robocopy to keep several directories synchronized between
geographically separated sites connected by a hardware-based VPN. We've got
burstable bandwidth at both sites up to 100Mbps, but are still getting much
slower transfer speeds than expected.

The sites are on opposite sides of the Atlantic, and traffic does cross the
public Internet -- which is admittedly not ideal, but even considering this
we should be getting much better throughput. At our fastest we're still only
getting .5% of the theoretical maximum or roughly .46 Mbps; the average is
actually much lower.

Both machines are W2k3 Storage Server with 512MB of RAM on fully swiched
hardware at 100-base-T. Ping times are consistently 80 milliseconds.

Any ideas on how I might speed things up a bit? Is this an inherent
limitation of the SMB protocol?

Many thanks,

J.

 

[Jerold Schulman]

I've been using robocopy to keep several directories synchronized between
geographically separated sites connected by a hardware-based VPN. We've got
burstable bandwidth at both sites up to 100Mbps, but are still getting much
slower transfer speeds than expected.

The sites are on opposite sides of the Atlantic, and traffic does cross the
public Internet -- which is admittedly not ideal, but even considering this
we should be getting much better throughput. At our fastest we're still only
getting .5% of the theoretical maximum or roughly .46 Mbps; the average is
actually much lower.

Both machines are W2k3 Storage Server with 512MB of RAM on fully swiched
hardware at 100-base-T. Ping times are consistently 80 milliseconds.

Any ideas on how I might speed things up a bit? Is this an inherent
limitation of the SMB protocol?

Many thanks,

J.

How are you measuring throughput?

What is your RoboCopy command line switches?



Jerold Schulman
Windows: General MVP
JSI, Inc.
http://www.jsiinc.com

 

[Jerold Schulman]

I've been using robocopy to keep several directories synchronized between
geographically separated sites connected by a hardware-based VPN. We've got
burstable bandwidth at both sites up to 100Mbps, but are still getting much
slower transfer speeds than expected.

The sites are on opposite sides of the Atlantic, and traffic does cross the
public Internet -- which is admittedly not ideal, but even considering this
we should be getting much better throughput. At our fastest we're still only
getting .5% of the theoretical maximum or roughly .46 Mbps; the average is
actually much lower.

Both machines are W2k3 Storage Server with 512MB of RAM on fully swiched
hardware at 100-base-T. Ping times are consistently 80 milliseconds.

Any ideas on how I might speed things up a bit? Is this an inherent
limitation of the SMB protocol?

Many thanks,

J.

How are you measuring throughput?

What is your RoboCopy command line switches?



Jerold Schulman
Windows: General MVP
JSI, Inc.
http://www.jsiinc.com

 

[James Hancock]

Thanks for the reply. My switches are as follows:

/NDL /S /E /COPYALL /X0 /M /R:10 /W:30

I'm calculating the throughput below using the robocopy statistics generated
at the end of the job. Manual tests using sftp and ftp indicate better
throughput (3Mbps) but still not great considering.