Use robocopy for switching file servers

[Thrasonic]

Hi all. I have a massive file copy I need to do as I'm moving data from fileserver1 to fileserver2. There's so much data, and it copies so slowly, that it will take possibly as long as 24 hours for the robocopy to complete. Also, there's no way to keep the users out of the files while the copy is going on.

Because of this I was wondering how I could use robocopy to get the job done. If I use the /MIR switch I know it will create an exact copy of what's in fileserver1 and place it on fileserver2. Once that's done I'd like to run another robocopy that only copies files that have changed since the last copy. I'd like to think that would result in a copy that would go very quickly. The only problem is I don't know how to do that.

Can robocopy do that? If so, how?

[rraehal]

By default robocopy will check all files for their version using a checksum. If a file is changed it will be copied and if it has not changed it will not be copied.

You can use the basic syntax like this. If any files are deleted the MIR will also remove the files on the target (server2). /r and /w are simply the retry count and wait times before retrying.
robocopy \\server1\share1 \\server2\share2 /MIR /r:3 /w:3

I use this syntax when performing this type of copy. I use /COPY:DAT so that security information is not copied but inherited from the target server NTFS permissions. I use /e to copy empty directories because we have some folder structure templates that are empty so when project are created they have all the folders for our software application.
robocopy \\server1\share1 \\server2\share2 /MIR /COPY:DAT /r:3 /w:15 /e


Robocopy is a file transfer utility. That means if 1K of a 100MB file gets changed all 100 Megs have to be copied. Other technologies will provide better transfers if this happens regularly.