February 7, 20251 yr Is there a way to verify and correct a disk from parity? I know that the parity check verifies the parity disks but I have a disk that has reallocated sectors. I have no intention of replacing the disk at this time because this could just an anomaly but I'd like to verify that the disk contents are ok. So, to me, that means that I should be able to use parity to verify the disk. Is there a way to do this?
February 7, 20251 yr 3 hours ago, TimTheSettler said: a disk that has reallocated sectors. I have no intention of replacing the disk at this time because this could just an anomaly reallocated sectors are not an anomaly. That SMART attribute won't reset or decrease. The disk had some bad sectors so it had to reallocated those with some if its spare sectors. Nothing to do with the software or a temporary problem. But, if there are not many reallocated, and they aren't increasing, it's probably OK for now. Post a SMART report if you want another opinion. You should see a SMART warning ( 👎 ) on the DASHBOARD page for that disk. You can click on it to acknowledge and it will warn again if it increases. Do you have Notifications setup to alert you immediately by email or other agent when a problem is detected?
February 7, 20251 yr 9 minutes ago, trurl said: A non-correcting parity check will verify that all disks are in sync. If a bit on some disk is not in sync, no way to identify which disk it might be on. https://docs.unraid.net/unraid-os/overview/nas/#parity-protected-array
February 8, 20251 yr Author On 2/6/2025 at 11:18 PM, trurl said: reallocated sectors are not an anomaly. That SMART attribute won't reset or decrease. The disk had some bad sectors so it had to reallocated those with some if its spare sectors. Nothing to do with the software or a temporary problem. The point of my post was not to complain or panic about the reallocated sectors. I've run into this problem many times in the past and I usually acknowledge the error and leave the drive as is. I'll replace the drive only when the event shows up again. That's why I like unRAID. I have my parity disks as insurance and I can monitor the situation. On 2/6/2025 at 11:20 PM, trurl said: If a bit on some disk is not in sync, no way to identify which disk it might be on. I know what you mean but if you have two parity disks then identifying and fixing a problem is possible. Let's say that the parity has discovered an anomaly. If there are two parity disks then there are three sources of information. If two of the three match then it's a safe assumption that the majority is right. The third disk should be changed to match the other two, whatever disk that might be (the original or one of the parity disks). I like the idea of having parity to replace a disk but it should also be used to verify a disk if/when that disk has a SMART error. This would allow you to verify if the disk is still ok or at least that the data is still ok until the next event. The person then has some time to replace the disk.
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.