I’ve adding seven WD20EARS to a five WD20EARS array using ver. 4.7’s web interface. The new drives were assigned. The array was started. And the clearing process started. After ten hours I used the web interface to check the progress. The web page opened after a three minute delay and indicated that the clearing process was 30% completed. Checking the status five hours later, I’m unable to open the  web interface. I can telnet to the unraid server. Is there any way to check the status of the clearing process via a telnet session? Is there a log file that will show the progress?

Clearing a 2TB drive typically takes between 6 and 10 hours.

 

The process that drives the clearing and the web-interface is known as "emhttp"

 

You can see if it is still running by typing

ps -ef | grep emhttp | grep -v grep

 

The log file is the system log.  You can copy it to your flash drive by typing

cp /var/log/syslog /boot/syslog.txt

 

If emhttp is not running, there will probably be an error in the system log.

 

Joe L.

 

Thank you for your quick reply. When I started the array I was surprised to see that clearing was required. When the array was first established, clearing was not required. I run a parity check every month. So far no errors. But if any errors occur I’ll swap out the drive. Can additional drives be added to an array without running the clearing process?

 

Thank you for your quick reply. When I started the array I was surprised to see that clearing was required. When the array was first established, clearing was not required. I run a parity check every month. So far no errors. But if any errors occur I’ll swap out the drive. Can additional drives be added to an array without running the clearing process?

 

Yes, but only if they are pre-cleared.

 

The clearing was not necessary until after you had assigned a parity drive.  Once you did, the clearing (or pre-clearing) is needed to maintain parity.

 

Pre-clearing is done before you assign the drive to the array, and can be done with the array on-line, so your family does not see an extended outage just because you are adding a new drive to the array.  A HUGE benefit of pre-clearing is that it also is a burn-in period of the drive before you put your data on it.  (The pre-clear script does much more than the unRAID clear it is performing right now on your disk.)  A disadvantage is that pre-clearing a 2TB drive can take from 25 to 35 hours, but again, your array is online during this period.

 

Adding a pre-cleared disk you your array takes just a minute.  The time it takes to stop the array, assign the new drive, and then start the array once more.  Most people pre-clear their disks.

 

Joe L.

Would it be possible to remove the parity drive? Add the additional drives without clearing (or pre-clearing). Then assign a parity drive (recalculating parity). While preserving the data on the original drives.

Yes, but it is a bad idea. One out of five drives fails pre-clear and with out the pre-clear test those bad drives would fail in your array. Do you feel lucky?

Good advice. I’ll pre-clear the drives. Thanks for your help.