Unraid 6.10.3 Find parity disk

[requiRe]

Hello everyone,

 

until today I used Unraid on a Lenovo Thinkcentre Tiny together with an external USB disk enclosure with 2x 3TB drives.

Today I built a new system where the drives are finally connected directly via SATA and I have room to expand and upgrade in the future.

Unfortunately I had to learn that the USB disk enclosure messed with the device IDs and thus Unraid showed them as "wrong" after booting up the new system.

 

As data disk and parity disk are the same model of disk, I dont know which is which. I think I might know which is the parity drive (I marked the disk which was in Slot 1 of the enclosure, and I think that was disk ...0:0 in Unraid (parity), disk ...0:1 being Slot 2), but I can't really be sure. I did a lot of googling and tried some help of another post - to add both disks as data without a parity disk and see which of the drives doesnt have a file system. The thing is: both show up with xfs and the same size on the main page of Unraid. So that didn't really help.

 

I am a bit out of ideas. I guess I have to move the drives back to the USB enclosure, roll back to a flash backup and better mark the disks next time. But maybe somebody has another idea.

 

Thanks!

[John_M]

In the unique situation where you have one data disk and one parity disk and they are both the same size, their contents are identical because that's how even parity works.

 

You could probably assign either as either and it would be ok. However, you might want to adopt a more cautious approach.

 

Here's what I'd do. I'd choose one of them and temporarily disconnect the other (so if things go wrong you at least have a second chance). Do a new config and allocate your chosen drive as disk 1, no parity. Start the array and check that your files are ok. Once you're happy you can shut down, reconnect the other drive, add it as parity and let it rebuild.

[requiRe]

On 8/3/2022 at 6:22 PM, John_M said:

In the unique situation where you have one data disk and one parity disk and they are both the same size, their contents are identical because that's how even parity works.

 

You could probably assign either as either and it would be ok. However, you might want to adopt a more cautious approach.

 

Here's what I'd do. I'd choose one of them and temporarily disconnect the other (so if things go wrong you at least have a second chance). Do a new config and allocate your chosen drive as disk 1, no parity. Start the array and check that your files are ok. Once you're happy you can shut down, reconnect the other drive, add it as parity and let it rebuild.

Thank you! Thats what I am gonna do. I will report back.