RileyNZL wrote in post #16579425
The problem with RAID 5 systems which most NAS's use (And drobo's) is that the platform is designed for high up time, not data protection. If a drive dies and you need to do a rebuild, the chance of a second drive failing while doing the rebuild is very high, especially with todays large drive sizes. Second to that, unless you're using enterprise level RAID cards (and possibly DROBO's) if you lose your motherboard/raid controller, you also lose your whole RAID5 array.
Mark0159 wrote in post #16578762
If something where to happen to the NAS, even if the HDD's are ok then you can't access the data. This is the problem with a NAS system. The data is store on it's own file system so a different type of NAS can't access the files.
This is not a raid / HDD / hardware forum, so I will not get into it too much.
But to be simple clear, both of you are completely wrong.
Today's technology is way more advanced than how you describe it, which was true maybe 20 years no. Not now.
If your raid controller or motherboard dies, all of your data is still accessible using a different raid card or motherboard (the raid and data is stored on the HDDs along with the file structure, and not on the controller). Raid technology is universal (even it it varies slightly between controllers). You can move a raid between a motherboard and a dedicated controller if you know how. And this can be done without touching your data. Even if one of your raid drives is lost.
I can vouch for all of this. It works. Seamlessly almost if you know what you are doing.
Regarding chance to losing a second drive on a raid5 or a third on a raid6 or 2 on the same strip of raid 10, or 4 on raid 60, well, it can. Also your computer can die because of an electricity spike, or you can lose several days of data if your HDD dies without a backup. And your external drive can suddenly be dead when you want to restore something off it. **** happens.
But if you use several ways to save your data, you will be covered about 99.9% of the time from any problems.
Also, there are several different raids beside the normal ones. Disk extender, raid-z, unraid and other sort of software raid to spread files between HDDs (which some don't have an active backup if a HDD dies, but still not everything is gone).
Anyway, as this has gone way too much into hardware mode, I suggest two things (three if you want to go the extra mile):
1. Using 2 HDDs in raid 1 (which is just a mirror, no strips or parity). This way there is always a copy on the same computer. Using 2x4TB of drives will make sure that even if one dies, there is always a second with exactly the same data available. You will never be "offline" from your data.
2. Files you have edited and are important to you, to save on a second 2TB+ external drive once a week (which can be setup automatically, so you don't even have to do anything beside hooking the HDD and let it run its automatic backup).
3. If you really want to be sure, duplicate that external drive to a second one and save in a different place.
This whole exercise really depends on how much data you have.
I personally have 10TB of data at home (work related) and 2TB of data stored away which is more important to me (family, projects and so on which I will rip my already missing hair if I lose it).
You don't have to use enterprise level drives. They cost a fortune. There tons of solutions like the WD blues or reds, but green or barracuda can be just as fine if you run them in raid 1 and aren't expensive at all.
I hope this wall of text (which was supposed to be simple) is more clear.