I had to play inside my server this month and it happened twice that a cable got loose and one of my hdd got disabled by Unraid. I was surprised to find out that there is no straightforward way to re-enable a drive when you know it is good. I had to rebuild twice and it take ages. I found some way to do it while searching but it involved playing with reconfiguring the array and it was a bit scary to do. It would be nice to have an easily accessible way of re-enabling a disabled hdd straight from the GUI.

 

Thanks!

Rebuilding is required because the disabled disk is out-of-sync with the array. Just enabling it without rebuilding will not fix the out-of-sync. The only other possibility is to rebuild parity instead so everything is back in sync, but since it is the disabled disk that is out-of-sync it usually makes more sense to rebuild it.

But what if the array is not auto-started if a disk is found missing/disabled? Wouldn’t the disabled disk still be in sync and could be re-enabled without a rebuild?

No it is still out-of-sync.

 

Unraid disables a disk when a write to it fails. After a disk is disabled, Unraid does not use it again until rebuilt (or new config as mentioned). Instead, it emulates the disk from the parity calculation using parity and all the other disks. Emulation includes writing. That initial failed write, and any subsequent writes to that disk, updates parity, so those writes can still be recovered by rebuilding the disk.

 

Has absolutely nothing to do with autostart since it is already out-of-sync as soon as it is disabled.

 

52 minutes ago, SkinnyV said:

I found some way to do it while searching but it involved playing with reconfiguring the array

If you did New Config without rebuilding parity, then your array is out-of-sync. You must do a correcting parity check to get it back in sync. And then you should do a non-correcting parity check to verify that you have no sync errors. Exactly zero sync errors is the only acceptable result and you aren't finished fixing things until you get that result.

I understand, thank you for the explanation.