First, some background on out situation. We're a small-medium business who has around 20 TB of data on two different NAS's, and that number grows by at least 10% annually. 90% of this data we need to keep for legal reasons related to the work we do, and all of it needs to be accessible. Less then 1% changes daily, but we still need to be able to view and access the other 99%.
Now as the end of the year approaches its time to start our annual backup. The last 5 years we've simply plugged several external HDD's into a PC on the network and used robocopy to copy the two separate NAS's to the externals. Then in early January we'll go back and in an incremental backup to the same drives to make sure we've got anything that changed since. Finally the CEO takes these drives to his house for safe keeping.
We also do a nightly incremental backup of the NAS's to another set of external HDD's. So solutions I'm looking at now for the annual are also trying to take into account our incremental nightly backups, to try and make both better.
So - goals: To complete the annual backup as easily, securely, and quickly as possible. As we're a small business cost is always an issue, and anything I come up with I have to be able to justify the costs to the higher ups.
So far I've considered tape backup, and just another NAS where once a year we pull the drives out to give to the CEO, and buy another set to rebuild a new backup.
I'm pretty new when it comes to backing up such large amounts of data, and any help or tips you have would be much appreciated.
So, any recommendations on how we could make our backup process better?
PS - Both NAS run on raid6.