4000 boxen? Just restoring from backups? There's a quick way to completely fail any RTO you might have set.. 1 week would give you 2.5 minutes for each box..

4000 boxen? Just restoring from backups? There's a quick way to completely fail any RTO you might have set.. 1 week would give you 2.5 minutes for each box.. (obviously you could do things in parallel - but not all at once) If you had to pull backups off tape - then you'd be limited by number of tape drives - 100 maybe? If you were pulling it all in off a SAN/VTL then you've still got a whole pile of bottlenecks - disk speed, fabric, network, etc.. Remember: Backups are not a DR solution. (and conversely - a hot-site or equivalent is not a backup solution!)