I'm using 2-bay drive Synology (implies I'm using linux mdadm software based RAID system).
The motivation for doing so is to lessen the time rebuild RAID-1 array after it goes degraded. I currently have two 4TB drives of class 5400 RPM and it take an entire day and perhaps few more hours to rebuild the entire array. Imagine how much more it would take if I upgrade to 8TB or 12TB!
Say if I have 2 8TB physical drives, I'd like to set up 2 RAID-1s having 4TB each raid array instead of 1 RAID-1 array of 8TB. So that in case it loses integrity, I would only need to sync just 4TB instead of entire 8TB. But the downside would be that if the 2 raid arrays both fail in which case I would have to sync 2 4TB arrays.
Is it even possible to setup 2 4TB RAID-1 arrays on 2 physical 8TB drives?
If it's possible and I have it set up, is it more probable that when integrity failure happens it would happen on both raid arrays than just 1 of the 2 raid arrays?
In a 2 raid-1 arrays, does a failure in one array results to failure of the other array? Because if it does then it will defeat the purpose of having multiple arrays.
Will there be any difference between 2 raid-1 and 1 raid-1 arrays (both running on just 2 physical drives) in terms of stress it would put on the physical drives?
Take note that I intend to create one volume per array which means, having 2 arrays of 4TB means I will have 2 volumes of 4TB each. The two volumes will be independent from one another so as the 2 raid-1 arrays.
Looks like mdadm actually supports it but Synology, while uses mdadm, doesn't.