Hi,

 

I just installed a new WD20ERAS drive on my UnRAID box. And went straight to the web gui, set it as a new drive, and "started" the array. It's been going for a few hours and it's still around 14% (a lot slower than last time I added a drive, btw).

 

Looking through the forums I read that there's a pre-clear script that I could use while keeping the array online. Of course, now I'm in the middle of the clear, and cant find a button to stop it.

 

Is there any way I could do that without potentially destroying all my data?

 

regards,

del

I believe you can just stop the array and uassign the disk from your device tab. After the disk is unassigned restart up your array.

 

Then use this script.

http://lime-technology.com/forum/index.php?topic=2817.0

How do I stop the array? There is no stop button in the web-gui.

At this point, there is nothing other than powering down by pressing the power button for 10 seconds..  I have no idea if the array will start a parity check upon power restore, but odds are it will since it was not cleanly stopped. There is a chance it will not, because the "clear" might be taking place while the array is off-line.

 

The speed of the built-in "clear" is dependent on the speed unRAID can write to the disk.  It depends on the speed of the disk itself, the speed of the disk controller, and the total size of the disk.

 

Most disks can be written to at about 80 MB/s on outer tracks and 50 MB/s once you get to the smaller inner tracks.  If you figure an average of 15 seconds per Gigabyte, an a 2TB drive is 2000GB, you end up with  30,000 seconds, or about 9 hours to just clear the drive.

 

You've discovered exactly why the pre-clear script was written.  If you use the built-in clearing process, during the 9 hours, the server is unavailable and off-line.

 

If you use the pre-clear script, the server is available for all by a few minutes when you actually assign the drive to your array.  The pre-clear script does far more than the built-in clear of the drive.  It first reads the entire drive to detect bad sectors, then clears it, then re-reads it to ensure what was written could be read.  It takes a bit over three times the time the built-in clear to do the entire process.  Expect it to run roughly 30 to 35 hours on a 2TB drive.

 

Joe L.

Yep, I've learned to like the preclear script as well. I did 6 drives without locking up the machine. The only time I forgot about it was when I was tinkering with a 120gig drive and luckily I was able to stop it, which honestly I don't recall how I did it now, but I was able to and then ran a preclear on it.