We have a scheduled task that runs robocopy periodically to mirror a rather large folder structure from one server to another (thousands of folders, 100,000+ files, 50+ GB in size). There is a share on the receiving server where the mirror gets stored. We're running the task from the origin server connecting out to the share on the receiving end. Both servers run Windows Server 2003 and are connected to the same network switch (100Mbps).
The process will sometimes complete all the way through without error. More often than not, however, at some point during the process (seems random as to where), robocopy will fail with the error The specified network name is no longer available. It will wait 30 seconds and try the file again and eventually give up after a number of retries. Process will repeat at the next schedule interval and may complete... or not.
When this occurs I am not able to access the share at all on the destination server from anywhere on the network for up to 30 minutes. There is nothing else on the network using this share.
My question is what does this error mean specifically? Why is the share "dropping off" and becoming inaccessible? Is there a way to prevent it and get the file mirroring to be more stable?
Robocopy is merely reporting what Windows has told it, that the remote end is no longer available, which can be a right pain to debug.
If you have antivirus software on the machines do a test run with that disabled. It's possible that the AV scanner isn't keeping up properly and causes things to hang while it tries to catch up. If that works you may need to disable the AV scanner on at least one end for the duration of the transfer. Also ensure that there is no firewall involved that might misinterpret the traffic and cause the the connection to be broken.
As a side note, that's a lot of traffic over such low speed NICs. You might consider adding a 1GB NIC to each machine, possibly connected by a crossover cable if you have no suitable switch ports available, and having that traffic routed through those NICs.