Le 23/01/2013 16:09, Cousin Ricky a écrit :
> for Linux is most emphatically that RAID must not be used as a primary
> backup system.

If you expect RAID to cover failure, you would be in for deception.

My home system is Raid5, linux only. It should support failure of one
disk, but I know that two failures at the same time will just lost all
the content (of 5 drives). I keep an external backup (offline, over usb)
just in case (sync is low).

About raid, there is two cases: done by the motherboard, or only by the OS.

My motherboard is able to set some raid... but it fails once the usage
goes beyond 2 TB... (well, not fails, just corrupt... )

So, I went the pure-OS way. It's fine with ubuntu once you have found
the right iso & right steps (including the small step: allow to boot on
a damaged raid array, which is not set by default, so the raid can
continue to run in degraded state, but if you turn off the system,
you're dead if you had not repaired before the shut-down)

Now, for your setting: assuming your motherboard would support raid,
that you are willing to pay an extra drive (for nothing, in capacity),
you can:
* make a basic raid-1 (mirror) system via the motherboard, should one
drive fails, you turn the live one in non-raid and use it... transparent
to both Microsoft & Linux, but beware of the size limit. Cost: 2 drives
for the capacity of only one.

* make a motherboard raid-5 system (need at least 3 disks, more is
better), got the capacity of N-1 drives (and a descent speed too, due to
parallel read & write, for big files). Beware of size limit, can be
fine, and transparent to the Windows & Linux, so handling fault is only
a bios business. BUT you cannot have more than one fault at a time, and
if the motherboard dies, the disks might not be recoverable at all.
(unless you find exactly the same bios... good luck after 4 years..)

* Stop using windows and single boot Linux in softraid: no more size
limits, but still vulnerable to multiple failures at once (in raid 5).
At least, motherboard changes is transparent.

I do not know how to have windows on raid, when not done by the
motherboard (and re-installing windows on a pre-build system to turn it
on Raid can be troublesome).

If you intend to use SDD, do not go raid!

If you have a usage for a laptop, synchronising it with a desktop can be
painful on the long run. And external drive are the best backup for laptop.

PS: raid-6 is not worth the slowdown & complexity, unless your data is
very precious and you are ready to have 2 wasted disks.

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