I wish to purchase hard disks for purpose of storing financial tick-data. As per my calculations, 6 TB will be required for 3 months of history. Beyond that I may later decide to keep deleting if I don't need or to buy additional storage if I certainly must store longer history.
I do not want to risk losing any of the latest 3 month historical data due to hard disk failure, that is why I intended to set-up RAID 5.
My question is: Which hard disks should I buy?
My constraints/doubts are:
1) I don't wish to spend money on SDDs, it's hefty price is not worth the additional read-write speed for my purpose.
2) I immediately want to buy just one hard disk to take one time data load from someone, but want to make sure I can use this hard disk later (in a matter of weeks) when I do end up buying other hard disks, and whatever else hardware is required to set-up RAID etc.
3) Will setting up RAID 5, using say four 2 TB HDDs give me 6 TB of storage?
4) Will this RAID system necessarily need a container (rack) and cooling ? Any recommendations for a cheap but reliable rack if so?
4) I need the hard disks to be easily removable and mobile (not crash due to speed bumps on road), because I might need to, say once a month, take one out and transport it locally to get it loaded etc. (can one even do that with a RAID 5? i.e. take out one disk, get more data on it and put it back in the rack and expect all disks to magically "get that data"?)
5) I am not sure whether I will use this on linux or windows yet, so are there hard disks and RAID that will work on either linux or windows? Or is that a decision I must make now?
6) is NAS something I need here? Or that's an overkill for my purpose? (A cursory look at NAS prices for 4 HDD racks, sounded expensive to me)