how do you resume a preclear

[comet424]

hi  so I was preclearing a 12TB drive  been 5 days  and starting cycle 3 of 3.. .  kids pulled the power cord and she shut down..

 

I booted up and I did the resume preclear  but when I do PREVIEW  eye button...  and it shows the screen it says Type Yes to proceed.. how do I type yes?

[comet424]

rebooting and resuming does nothing.. I thinking running it once  should be good.. as takes 48 hours to do 1 cycle of the 5 tests

 

 

[BobPhoenix]

What I do is just run the last cycle or two depending on where it was when I canceled it.  I tell it to skip the pre-read if it was past the initial pre-read on the first cycle.

[comet424]

ya It was like the last 2 of 5 and I think I was doing the last cycle 

how do you skip it?  didn't know you can skip in the gui.. I read about script and such I even typed YES in script save and rebooted and even that didn't work  is it a glitch...  I read also  that you don't ever need Preclear since Unraid 6  as unraid preclears it in the background some how I dunno  

[wgstarks]

13 hours ago, comet424 said:

I read also  that you don't ever need Preclear since Unraid 6  as unraid preclears it in the background some how I dunno

This is true. In previous versions of unRAID, it was necessary to stop the array while clearing new disks so a preclear was very handy to avoid this. Now it’s no longer necessary. UnRAID will clear a disk while the array is running. Some people still use preclear as a tool for testing new drives before installing them though.

[trurl]

14 hours ago, comet424 said:

I read also  that you don't ever need Preclear since Unraid 6  as unraid preclears it in the background some how I dunno  

Unraid "clears" (zeros) a disk when it is ADDED to a NEW slot in an array that already has valid parity. This is so parity will remain valid since the zeros has no effect on parity. This is the only time Unraid needs a clear disk. Old versions of Unraid would take the array offline when it needed to clear a disk, but it does the clear with the array online in recent versions.

 

"Preclear" was invented to "clear" a disk before (pre) adding it to a new slot to avoid having the array offline. The only reason to use preclear now is to test a disk, and possibly "burn-in" a disk to get it past "infant mortality".

 

 

[comet424]

ah ok  I thought  preclear  was just for that sole purpose of testing the hd to make sure it doesn't fail...  I wasn't able to fix the preclear to get it restarted  Type Yes never an option  so I just gave up on it..  

 

so why would the array go offline?  doesn't it always have to go offline... when I add a new disk  I have to turn off Array  select Disk 5 say select my disk then restart the array...

or are you saying you can add disk to the array without having to shut off the array... and say add it to slot 5 as an example

 

 

[itimpi]

43 minutes ago, comet424 said:

so why would the array go offline?  doesn't it always have to go offline... when I add a new disk  I have to turn off Array  select Disk 5 say select my disk then restart the array...

or are you saying you can add disk to the array without having to shut off the array... and say add it to slot 5 as an example

 

 

You are right that to add a disk the array has to be stopped; the disk added; and the array restarted.

 

The change is that in earlier releases of Unraid when the array was restarted the Clear process would start and the array would be unavailable until it finished (which could take hours).   Under V6 the array is started and then the Clear runs in parallel with the array started so the array downtime is seconds/minutes rather than hours as used to be the case.    When the Clear finishes you are then given the option to format the disk and actually start using it.

[comet424]

oh ok wow eh  ya takes forever..  I know doing the PreClear  program to do 1 12TB drive 3 times took 6 days  so your looking at one cycle 2.5 days then your array be down for … I only started  at 6.5.2 version something like that  I got it summer of last year

I still like this program better then freenas xpenology free4nas etc..  1 for the adding a new HD and you can expand... and 2  Plex updates when I add new content.. Freenas  wouldn't update  id have to manually go and do it.. which sucked..   only thing I find is when I transfer files to the unraid I was hoping to get 100meg/s  since they all 7200rpm 256cache drives so speed is not the best... but I  accept the speed lost for the just adding a new hard drive  to make array bigger.. or swap out my 2tb and replaced it with a 12 or whatever size ….

[itimpi]

The Unraid ‘clear’ is equivalent to just the ‘write’ phase of the pre-clear script so takes nowhere near as long as the pre-clear.   Unlike the pre-clear script the built-in ‘clear’ option does not check that the writes all went without any error as it does not read back the results.   It can still take hours on large disks but it is nowhere near as long as a pre-clear cycle.    In my experience it the elapsed time of the Unraid clear is about 25% of a single pre-clear cycle.

[comet424]

oh that is a significant time difference..  but then still good to use preclear for drive failures...  

as I had my parity drive fail other day  just bought the HD  in novemeber  so I just waiting for WD to send the 12tb drive but frig I going to have to preclear it so  it be another 6 days for that puppy too lol so I know drive doesn't fail in use