How do *you* handle data migration projects?
Just wanted to pick some brains out there as this seems to be a fairly common practice, at least with the positions I have been in over the years.
When data centers need to either be consolidated or moved, it seems the first method that comes up is tape, because it should be simple: Backup all the data at site A, ship the tapes to site B, restore them to newly built clients and everybody goes to bed happy.
Except I have rarely seen that - maybe the sitautions I have been in have just been loopy (or maybe its me!) but it seems as time goes on and data gets larger that this seems to be a pretty painful process. Recently I have been dealing with things that I never thought would be issues, like different libraries and tapes making things challenging. On top of that a lot of times the data center that is on it's way out is usually unwilling (or unable) to get the environment up to date and/or stable; after all it's "going away soon" so why bother? That has left teams that I have been on floundering around with outdated software and hardware trying to make the best of it.
Anyway I know there are a lot of options out there: Data Domain, NBU Appliances, MSDP, etc. Most are EXPENSIVE and it's pretty rare for the powers that be to be convinced to shell out that kind of money just to move data - I think a lot of it comes down to old fashioned thinking that just dumping everything on tape should be good enough. And usually it is - but I have found that unless an environment is well tuned and in good shape once you start talking about single clients with around 20TB of data, things tend to take a lot longer than planned, even at ideal transfer rates which is not always attainable.
So what ways have you fine folks worked out when it comes to moving lots of data like this? I am mostly interested in the "One off" data center migrations that I seem to find myself wrapped up in.