Disk showing red cross - replace or can I fix it?


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Hello everyone.

Hope all is well.

 

Yesterday, I had a red cross on Disk 2.

The disk is months old and was subject to a pre-clear before going in so I my gut feeling is that the disk is okay.

 

So, my question is the following...

 

Is there a way to remove drive, preclear it and re-use it and get Unraid to rebuild onto it without losing data?

 

Notes

I have changed the SAS cable and connected directly to a SATA connection but still get the red cross.

Before doing this and rebooting I could get SMART data. After reboot, no SMART data is available.

 

I look forward to your advice and expertise.

 

Many thanks.

Al

 

kraken-diagnostics-20220805-1706.zip

Edited by alinkognito
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Aug  4 20:06:48 Kraken emhttpd: Unraid(tm) System Management Utility version 6.10.3
Aug  4 20:17:11 Kraken root: Fix Common Problems: Error: disk2 (TOSHIBA_MG08ACA16TE_Z9Q0A0NUFVGG) is disabled

Disk2 was already disabled when you booted. Diagnostics only contains current syslog, which is just since last boot, so we can't tell anything about what might have disabled the disk.

 

But it looks like you are still having connection problems with disk2 and no SMART report for that disk in diagnostics.

 

Check all connections, both ends, SATA and power, including splitters.

 

Then post new diagnostics.

 

 

 

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  • Solution
28 minutes ago, alinkognito said:

remove drive, preclear it and re-use it and get Unraid to rebuild onto it

Not exactly wrong, but mostly unnecessary.

 

There is no reason to preclear the disk. There is only one scenario where Unraid requires a clear disk. That is when adding a disk to a new slot in an array that already has valid parity. This is so parity will remain valid, since a clear disk is all zeros which has no effect on parity. In this scenario, if the disk hasn't been precleared Unraid will clear it.

 

Other than that one scenario, preclear is only for testing, and not really even necessary for that.

 

When you use a disk for rebuild, the entire disk is overwritten, so it doesn't matter at all what is on the disk, clear, empty, full of data whatever.

 

Also, it isn't even necessary to remove the drive, all you need to do is start the array with the drive unassigned to get Unraid to consider the drive a replacement when you reassign it.

 

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