Hi, > > RAID-5/6 with heterogeneous devices. [...] > I've thought about this occasionally but don't think much of the idea. > It seems nice until you think about what happens when devices fail > and you need to integrate hot spares. > Clearly any spare will need to be as big as the largest device. > When that get integrated in place of a small device, you will be > wasting space on it, and then someone will want to be able to > grow the array to use that extra space, which would be rather > messy. > > I think it is best to assume that all devices are the same size. > Trying to support anything else in a useful way would just add > complexity with little value. I see your point and I also agree that complexity might be too much. Nevertheless I disagree about the "wasting space", since I can see a scenario where there is even more wasting. Let's assume we have a RAID-5 with 7 disks. Each time an HD fails, we will replace it with a larger one, since this will be cheaper. Once we replaced 3 HDs, with could use the unused space in RAID-5 again. Unfortunately, with the current features, we will have to wait to fail all the 7 disks. So, with 6 HDs replaced with larger ones, we will have a lot of wasted space. Of course, unless we did a clever partitioning at very the beginning. But again, I do agree the complexity might not pay off the advantages, maybe better the "clever partitioning". Thanks, bye, -- piergiorgio -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
