teceem: I read/heard somewhere that when a NAS (like Synology, QSNAP, ...) fails, the hard drives (in RAID) inside can't be accessed in another system (regular PC/OS). I haven't really researched the details...
AB2012: I'm fairly sure that if the NAS formats the drives as EXT4, then in the event the NAS unit (not the drives) fails, you can emergency mount them in a live-boot Linux distro (eg, Ubuntu or LInux Mint) to copy them onto another drive. Obviously Windows has no native EXT4 support. There are 3rd party utilities out there that add a driver that can read EXT4 file systems, though from what I've read they are less advisable if you want to return a drive that was part of a RAID set into a new NAS as Windows may perform some background "maintenance" or write "System Volume Information" files that can could break a mirror set, so it's best to use a Linux distro with native EXT4 support for the "cleanest" emergency access.
Various NAS software will use various file systems, some may even be prioretary (although that is rather rare) and it has nothing to do with what system they run on.
Most off-the-shelf NAS run some *NIX derivative (usually some Linux with modifications, likely obscenely out-of-date kernel, etc).
You should REALLY
NOT *EVER* mount ANY ext4 drive under Windows (especially 10) under any circumstances. Let alone drive from RAID array.
It WILL mess with the drive. And it's almost 100% certain it will write SOMETHING. Which given 1.General shitty and incomplete implementation of those Windows tools 2.That drive in question would be front an array... well... you would be in for a hard time.
Just don't do it.
You don't cut corners in regard to backup drives unless you perceive the backup completely worthless.
Should your NAS mobo fail (some of Synology fail from time to time afaik, I don't know how about others, I personally wouldn't use off-the-shelf one anyway) mount it under some *NIX derivative (if you are new to these systems then better don't touch BSD and basically anything apart from Linux).
And for the love of God, MOUNT IT READ ONLY.
Or better yet. Get yourself a BIGGER drive (it absolutely HAS TO BE larger capacity than TOTAL [not just used] capacity of the rescued drive) and make sector-by-sector disc image of the drive in question and work on the image (mount it as a loop device, also, to save yourself pain 1.Mount it read only 2.Work on a COPY of the image, NOT on the original image file).
To make image I would suggest ddrescue (for a number of reasons), NOT plain DD (unless you perfectly know what you are doing).
Obviously it goes without saying that:
1.These tools (and Linux tools in general) will not hold you by hand and walk you through the process with multiple confirmations.
No. Tools on Linux are made with assumption that A.You understand what you are doing B.The command you confirm is the one you want to run (so ALWAYS check multiple times that your syntax is correct BEFORE confirming ANYTHING).
2.These tools can do a whole lot of things to drives, not just read, if you f up syntax in any way (basically all tools have case sensitive syntax, and Linux does no spellchecking of the syntax) you WILL regret it (you can for example nuke all your drives in the computer).
So ALWAYS make sure that the command you are about to use is correct.
It is also notable to mention that if you want to mount RAID volume then it is going to take bigger effort than mounting "normal" (non array) drive.
This all is obviously in regards of just failed mobo of NAS and NOT the drive itself.
It is possible to recover from failed drive but I don't feel like teaching you all IT forensics here now.
It's very complex subject to say the least.
As for the tools.
When I still used Windows I never used all those popular petty tools so I don't know those generally.
I would say:
1.Checksum EVERYTHING (use sha512), save checksums in safe place (checksum ORIGINAL files btw, NOT "all in one archive of all my games")
2.Total Commander (on NON STANDARD SETTINGS) copies with it's own method not relying on explorer, it's reliable, but you should always do checksum things after copying regardless.
As for Linux:
There is mountains of tools and it's up to personal preference.
Oh, and one more thing:
Be sure to be sane and use fairly NEW kernel / tools versions when mounting the drives.
The ext4 for example is being constantly worked on, improved, and gets added functionality.
If for example ext4 on your drive is version X+10 then some functionality of it will not work with tools of version X+4 (older, those are examples and not actual naming conventions btw).
Obviously if you have array and one of the drives dies you CAN connect it to Linux computer and replicate mirror on a new drive (from the working drive) but it takes knowledge to do so (obviously).
Generally speaking if you can afford it it's better to run DIY NAS made from computer.
That way you have MUCH better control and capabilities and less pain in case of troubleshooting.