I can only guess at exactly how long this will take but we are going to take the mail system down friday night and copy data from the existing spool to a mail spool on a new server friday night / saturday morning. We need to have the files be static during the copy, so all mail access will be suspended at that time. Mail will not be lost but delivery will be delayed until the copy is completed. There is approximately 6GB to be copied, and the limiting factor is going to be the speed of the existing system and that is also WHY we need to do this. The existing drive the spool is on is nearly saturated during daytime ours causing performance problems for the entire mail system. Moving the spool is only part of the whole process, moving services will follow, but it is the only part of the process that will require significant downtime.