Hi,

 

I have set up a new server with 6.1.7. 3 data drives and parity. Just assigned devices and started the array, but one drive reported as "Unmountable" - I had to tick the box to format it.  This completed OK (very quickly) and I have not yet transferred any data.

 

On starting parity check I get thousands of errors.. am I right in thinking I will need to pre-clear all the disks?

 

Thanks

Where did the disks come from? Had they previously been used in an unRAID server? Starting from scratch with brand new disks you would expect to have to format each of the data disks and build the parity (the former taking a few minutes and the latter several hours). Did you let all that complete or have you tried some trick, like trust parity?

 

No, you don't have to pre-clear any disks. There has never been a need to pre-clear disks. unRAID works perfectly well without it. However, it's use serves two purposes. Firstly, if you want to add a disk to an existing array if the disk is already pre-cleared it avoids the lengthy clearing process, which takes the array off-line. Secondly, it can be used as a fairly thorough test of a new disk to weed out those that fail early.

If the disks were precleared, then you are right, you shouldn't see any parity errors. HOWEVER...

 

Something isn't right with your description. If this was a new array, then you shouldn't have been able to start it without the initial parity build. A parity check after the build was complete should show 0 errors. I suppose if you had erroneously checked the box to say that parity was already valid when it hadn't been built yet could get you to your described state. Also, unless the drives had been formatted before in unraid, they will show as unformatted, so I'm having a hard time understanding how only one of the drives needed to be formatted.

 

Preclearing the drives isn't strictly necessary on a new build, you can just build parity based on what is on the drives already, but given the description, I'd recommend preclearing all the drives anyway to get to a known state with current smart reports.

 

Perhaps if you described more fully exactly what you have hardware wise and what you did setting up unraid then I might have a different opinion on what happened and what your best course of action is.

Thanks for the advice guys - I agree that something does not add up as it did not do a parity-sync.

 

Started again..

Tools tab - New Config - tick box, click apply, click done

Main tab - assign disks, click start (have NOT ticked trust parity)

 

It is now syncing parity.