@xrobau said in Changes at Sangoma:
@travisdh1 You still seem to be hung up on the RAID concept of parity. Truly, honestly, that's not how ZFS works. I cross my heart. It works on copies of data. Literal, exact, copies of the data.
Unfortunately, THIS is where the 'ZFS Can't expand a volume' problem comes into play. Because the location of those copies (on the physical spindles) is made by hashing the size and number of volumes in a zraid (I'm kinda simplifying here, but work with me!)
So if a ZRAID2 has 5 spindles, that means that a copy of block 1 of the zpool will be placed on spindle 1 at sector 10, 3 at sector 100 and spindle 5 at sector 500. The location of that doesn't need to be looked up, because it can be calculated.
The 'expansion' problem comes about because if you add another spindle to that ZRAID2, suddenly block 1 would be on spindle 1 at sector 10, spindle 3 at sector 500 and spindle 6 at sector 1000 (or whatever). So the location of the data would be wrong, and everything falls apart.
(Now, this is actually wrong, and there IS an index, but, that's advanced stuff, and this is good enough for you to get the idea).
Does that make more sense?
Not at all, because you are describing RAID 5/6. There is nothing special or different here.