Hi all,

 

I've got a 5 disk system with a parity disk that's slowly picking increasing UDMA CRC error count in SMART. The current disk config is:

 

3TB Parity

3TB Data

3TB Data

2TB Data

240GB Cache

 

I have another 2TB disk lying around, to help with what I want to achieve.. which is to replace the current 3TB parity disk with one of the current 3TB data drives.

 

Am I correct in thinking the steps below would be the process for achiving this swap?
 

1. Add teh spare 2TB drive to the array and assign to data
2. Stop the array
3. Unassign the 3TB data drive that will become the parity disk
4. Start the array - I'm assuming at this stage the parity drive will start to populate the remaining data drives with the data that was stored on the drive being unassgined?
5. Once the data is sync'd and healthy run through the process of replacing the parity drive:
   1. Stop the array
   2. Unassign the current parity drive
   3. Assign the now unassigned 3TB old data drive to parity
   4. Start the array and let the parity rebuild

 

I know ideally I should add a new drive of bigger capacity for the parity, however that's not an option at the moment and this is a secondary unraid device on the network.

 

Thanks in advance

23 minutes ago, teakmeister said:

picking increasing UDMA CRC error count in SMART.

This is usually a SATA cable problem, replace the SATA cable and see if it stops increasing.

Although booting the array and checking the CRC count, it's increased by only 2 in the last 8 weeks, so will probably leave as is, but would be good to check my understanding on the procedure.

Just now, JorgeB said:

This is usually a SATA cable problem, replace the SATA cable and see if it stops increasing.

 

Thanks JorgeB, just did a bit of reading up on the CRC Error count, and you're on the money, I'll be swapping the motherboard out shortly so will swap out the cable to the drive also. In the past 8 weeks it's only increased by 2 so nothing major. I've also checked the other drives and the remainder have only a max of 2 values recorded. Perhaps I was a little quick to panic 😁

2 minutes ago, teakmeister said:

but would be good to check my understanding on the procedure.

What would described won't work, you could manually move the data from one of the 3TB disks, then do a new config without it and use it as parity.

3 minutes ago, JorgeB said:

What would described won't work, you could manually move the data from one of the 3TB disks, then do a new config without it and use it as parity.

Awesome, thank you for confirming, appreciate your input.