In my journey to understanding the advantages of RAIDZ, i came across the concept of write hole.
As this page explains, a write hole is the inconsistency you get among the disks of the array, when the power is lost during a write. That page also explains that it affects both RAID-5/6 (if the power is lost after the data has been written, but before the parity has been calculated) and RAID-1 (data is written to one disk but not the others), and that it is an insidious problem that can only be detected during either a resync/scrub, or (disastrously) during the reconstruction of one of the disks...however, most of the other sources talk about it as it only affected parity-based RAID levels.
From what i understand, i think this could be a problem for RAID-1 too, as reads from the disks containing the hole would return garbage, so...is it a problem for every RAID level or not? Is it implementation-dependent? Does it affect software-RAID only, or also hardware controllers? (extra: how does
mdadm fare in this regard?)