I think this needs investigation of the restore log files by support staff. The only reasons I can think of why the restore process is slow is that the server does not handle computations on the untaring of the file correctly. Basically, the restore process only consists of standard Linux operations, like copy, rename, tar. There is not so much magic about it. The major hold-up during a restore is checking the file signature and untaring the .tar archive(s). Once it is untared, the rest of a restore is only a file copy operation. That ought to be as fast as any other file copy operation on the operating system. However, untaring and checking the file signature can take very long if the system does not have enough computational power, e.g. has a lot of load otherwise. If that is not the case, I don't see why a significant delay could occur.