It was quite a saga which was scary and time hungry to say the very least.
I was struck by the sheer number of responses and the myriad suggestions of alternatives.
I then recalled Anders C Madsen a photographer who has good knowledge about storage too, who came on one of my workshops last year.
I contacted him and asked him the best route to take and he suggested I investigate QNAP.
What is that?
QNAP Inc is the Quality Network Appliance Provider
I had never heard of them....and they still seem to be rather unknown in the Photographic world.
Based in Taiwan, they manufacture all different shapes and sizes of Network attached storage.
What appealed to me about them is the OS is Linux based not proprietary which means if something does go badly wrong a whole host of companies could help you recover data.
Anders recommended that I set the QNAP TS859 up in the RAID 10 configuration
Here is his reasoning...
"One of the really nice features is the ability to use RAID10, which is the absolutely fastest way to configure your disks - but unfortunately also the most expensive.
The thing is, you're basically using 4 pair of disks that mirrors content so if one disk fails, the other has the exact same content and chugs along until the defective disk has been replaced.
Lumping 4 mirrors together in one big "virtual disk" means that you are writing and reading to and from 4 disks in parallel, which again means a real life write speed of four times the write speed of one disk. If disk performance has ever been a problem for you, here is the best cure.
Read speed is also four times that of one disk but because of different cache systems in the disks and controllers, read speed is always a lot higher than raw write speed and thus less likely to be a problem anyway. Search operations that runs through large amounts of data is likely to benefit very much from RAID10 versus RAID5.
Problem is, using sets of mirrors means that your available disk space will be half of that mounted in the drive bays - that is, 8 x 2 TB disks will give you 4 x 2 TB available disk space (the other 4 x 2 TB being used for mirroring).
Using RAID5 instead will give you 7 x 2 TB available disk space (2 TB is used for something called "parity data" which essentially means that one disk can fail without causing data loss) but you will be writing and reading to and from one single disk at a time so it will be a lot slower than RAID10.