Hi, > I think just "block ABC is inconsistent" is sufficient. > user-space can then quiesce that part of the array, read the relevant > blocks, do any analysis that might be appropriate, and report to the > admin. personally I think user space is good for this kind of operations. I think the point here is not if this kind of recovery should be in kernel space or not, but to have this kind of recovery. > That is a very interesting threat scenario - occasional bit flip on > read between media and memory. I had a drive like that once. One > particular bit in the sector would fairly often return '1' no matter > what had been written. I had it in a RAID1 and it quickly made a mess > of the filesystem. In my case, a further analisys showed that the "bits" where always *written* correctly, but the reading operation was, sometimes, flipping bits. This was especially nasty, because, without "resync" the array would have been always fine. > As you say, there is nothing that md can or should do about this > except report that something odd is happening, which it does, and > report where it is happening, which it does not. Well, md specifically may or may not have the infrastructure to use the RAID-6 parity to correct this sort of issues. Nevertheless, using the RAID-6 double parity, in user or kernel space, is really one point for software RAID. 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
