I haven't added a new drive since I was on version 5. Today I added a drive and unraid made my "clear" it. Is this a built-in pre-clear since it is taking a long time. I also have installed the pre-clear plugin. What would be the difference between the plugin pre-clear and the clearing that's going on now? I do have the option to cancel it and I am not able to start my array, no options to start it. I thought back in the day with V5 you were able to use the array while pre-clearing drives, no?

 

I haven't added a new drive since I was on version 5. Today I added a drive and unraid made my "clear" it. Is this a built-in pre-clear since it is taking a long time. I also have installed the pre-clear plugin. What would be the difference between the plugin pre-clear and the clearing that's going on now? I do have the option to cancel it and I am not able to start my array, no options to start it. I thought back in the day with V5 you were able to use the array while pre-clearing drives, no?

By having unRaid clear your drive, the entire array is unavailable until the clear process is over (so that when the array starts, parity will be correct) - hours to accomplish this (probably 8 for a 3tb)

 

Hence the pre-clear script and plugin which allows you to pre clear the drives prior to adding them to the array, so there is minimal downtime (with the added advantages of post reads, etc)

 

v5 operated the exact same way as v6 in this regard

 

unRAID clears (all zeros) a drive whenever it is added to a new slot in a parity protected array so parity will remain valid. It takes the array offline while it does this. It has always worked that way. Note that this is not preclearing.

 

The preclear script was created specifically to clear a drive pre adding it to a new slot in a parity protected array. Then it can just be added since it has already been set all zeros so that parity will remain valid.

 

The preclear plugin is just a gui interface to the preclear script.

 

In addition to clearing a drive, the preclear script also tests the drive by reading it to make sure it can all be read, and to make sure it has been all zeroed. When unRAID itself clears a drive that you have added, it doesn't actually do any of these tests.

 

If you haven't set a parity disk yet, or if you are using the new disk to build parity, or using it to rebuild a data disk, it is not necessary to make it clear. Preclear is still often used just for testing in these cases.

 

Preclearing actually takes a lot longer than clearing because it also goes back over the disk and reads it all again after it writes zeros to it. In fact, the default is for preclear to read the entire disk, write all zeros to the entire disk, and then read the entire disk again.

 

Even though it takes a lot longer, most people won't use a disk without preclearing it, and some even run it through the complete preclear more than once before trusting a new disk.

 

Every bit of every disk in your array must be trustworthy because every bit of every disk is required to rebuild a failed disk.

 

All this has been discussed many times in the preclear threads. Very surprised you didn't already know all this given your post count.

 

 

I haven't added a new drive since I was on version 5. Today I added a drive and unraid made my "clear" it. Is this a built-in pre-clear since it is taking a long time. I also have installed the pre-clear plugin. What would be the difference between the plugin pre-clear and the clearing that's going on now? I do have the option to cancel it and I am not able to start my array, no options to start it. I thought back in the day with V5 you were able to use the array while pre-clearing drives, no?

By having unRaid clear your drive, the entire array is unavailable until the clear process is over (so that when the array starts, parity will be correct) - hours to accomplish this (probably 8 for a 3tb)

 

Hence the pre-clear script and plugin which allows you to pre clear the drives prior to adding them to the array, so there is minimal downtime (with the added advantages of post reads, etc)

 

v5 operated the exact same way as v6 in this regard

 

Thanks for the clarification. I did start the array without the new drive. Went over to the pre-clear plugin and saw the new drive there and clicked the "Start Preclear" link at the right of the screen and nothing happened. The column name is "Preclear Status". I would assume it should of started to preclear and show a percentage of how far it was done.

I haven't added a new drive since I was on version 5. Today I added a drive and unraid made my "clear" it. Is this a built-in pre-clear since it is taking a long time. I also have installed the pre-clear plugin. What would be the difference between the plugin pre-clear and the clearing that's going on now? I do have the option to cancel it and I am not able to start my array, no options to start it. I thought back in the day with V5 you were able to use the array while pre-clearing drives, no?

By having unRaid clear your drive, the entire array is unavailable until the clear process is over (so that when the array starts, parity will be correct) - hours to accomplish this (probably 8 for a 3tb)

 

Hence the pre-clear script and plugin which allows you to pre clear the drives prior to adding them to the array, so there is minimal downtime (with the added advantages of post reads, etc)

 

v5 operated the exact same way as v6 in this regard

 

Thanks for the clarification. I did start the array without the new drive. Went over to the pre-clear plugin and saw the new drive there and clicked the "Start Preclear" link at the right of the screen and nothing happened. The column name is "Preclear Status". I would assume it should of started to preclear and show a percentage of how far it was done.

Dunno.  I'm old school with preclearing, and still use the script.

I think I have seen it mentioned that there is an issue with the scripts, and so with the plugin, on 6.2 with the sfdisk command. There is a beta preclear plugin under development which uses a new script. You can find it in the last few pages of the plugin thread.

unRAID clears (all zeros) a drive whenever it is added to a new slot in a parity protected array so parity will remain valid. It takes the array offline while it does this. It has always worked that way. Note that this is not preclearing.

 

The preclear script was created specifically to clear a drive pre adding it to a new slot in a parity protected array. Then it can just be added since it has already been set all zeros so that parity will remain valid.

 

The preclear plugin is just a gui interface to the preclear script.

 

In addition to clearing a drive, the preclear script also tests the drive by reading it to make sure it can all be read, and to make sure it has been all zeroed. When unRAID itself clears a drive that you have added, it doesn't actually do any of these tests.

 

If you haven't set a parity disk yet, or if you are using the new disk to build parity, or using it to rebuild a data disk, it is not necessary to make it clear. Preclear is still often used just for testing in these cases.

 

Preclearing actually takes a lot longer than clearing because it also goes back over the disk and reads it all again after it writes zeros to it. In fact, the default is for preclear to read the entire disk, write all zeros to the entire disk, and then read the entire disk again.

 

Even though it takes a lot longer, most people won't use a disk without preclearing it, and some even run it through the complete preclear more than once before trusting a new disk.

 

Every bit of every disk in your array must be trustworthy because every bit of every disk is required to rebuild a failed disk.

 

All this has been discussed many times in the preclear threads. Very surprised you didn't already know all this given your post count.

 

I remember preclear for sure, but not the clearing. I guess it's been so long I needed to add drives the specifics were forgotten. I know in the last few years I've replaced many drives. Install and rebuild.

 

We would have many geniuses on many forums in the world if based on post count. My post count here is my participation and support of this product for many years.