Preclear plugin


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Hi all, i have a question if any have the respond, it would be appreciated...
Q.   if you have 2 unraid server can you preclear your disk in one and put it in the other serve, will it be recognize or i will have to preclear again?

Not in my experience. I have done this at least a half dozen times without any issues.


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Hi guys, this is a simple plugin that allows users to clear their disks before add them to the array.   The main characteristics of this plugin are: Modularity: can be used standalon

I think Thanks should be directed at all those members that have been dealing with the mess the last few months. @dlandon and @Squid have been working behind the scenes to try and clean up, and o

Dontlookoverthere over on the unRAID subreddit figured out how to get the plugin running again with a simple edit to the plg:   https://www.reddit.com/r/unRAID/comments/7wjpus/preclear_worki

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Every time I reboot my server, the Preclear plugin disappears as if it uninstalled itself (or something else uninstalled it). And I have to reinstall it again. Is this a known issue? Anybody else seeing this issue? It's not happening with any of my other plugins.
 
I'm on 6.9.0-beta30 with trial key.
Ok, I think I fixed the bug. Please update and test it if you could.

Thanks for your assistance.

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I think I'm having an odd problem with the plugin, or I'm doing something that completely isn't supported and don't realize it...

I have a 2 bay external USB 3 sata desktop thing.  Something like this but a different brand.
image.png.388607eed444b03c96531e1647b14e11.png


I have several drives I wanted to test and preclear.  I put 2 in that unit, one 2TB drive and one 6TB drive.

They detected in unassigned devices.  Though.... if the end of the names seem strangely familiar.

 

image.thumb.png.9fbaf532402044c35ce9337c241c7a5c.png
 
(The 3rd disk there that is preclearing is a 6 TB connected internally (was connected and preclearing before connecting this USB desk station thing)

I went into Tool > Preclear > and started to preclear the 2TB drive but when I did the link on the right side to preclear the 6TB drive was no longer there.  I stopped the preclear on the 2TB drive Now when I click the preclear link on the lower 6TB drive (the one not already running that is in the USB encloser) it reports as the 2TB drive.
image.thumb.png.6cafff32f25e1fd56023d07a33adf9b2.png

Any ideas whats going on here I'm more than a bit confused.

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Messing around with it I flipped the disks in the external USB desktop thing.  The Identification strings for both drives in unassigned device now appear to be the S/N of the 6TB drive.  And the issues above are now the same but for the 6TB drive now instead of the 2TB drive.

Maybe my USB enclosure is just a kinda garbage and doing some wacky stuff with drive identification?

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44 minutes ago, snowmirage said:

Maybe my USB enclosure is just a kinda garbage and doing some wacky stuff with drive identification?

This.

 

USB is the worst possible choice for external drive connections. SAS and eSATA are the only consistently reliable ways to connect to hard drives in a separate enclosure.

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1 hour ago, Maddeen said:

@gfjardim May I ask you, if I can run this on two disks simultaneously? 

Tomorrow I'll receive two new 4TB Ironwolfs and due to the very long process time it would be very nice if it works :)

Thank you

Yes so long as your disk count doesn't exceed the maximum amount of disks on your Unraid licence. I often run preclear on multiple disks at the same time. 
 

Licence Disk Allowances:

  • Basic = 6
  • Plus = 12
  • Pro = Unlimited 
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  • 2 weeks later...

Hello guys!

I just finished successfully the preclear of two disks. However, I am unsure what the Status of the S.M.A.R.T section could mean. I got on both disks multiple status of 9-Power_On_Hours and 194-Temperature_Celsius. Googled it and tried to find something in the forum, however I still do not know if that is a "bad sign" or something related to early mortality. Does anybody know what this means an if it is problematic?

 

Thank you for your help!

 

Disk 1:


 	
############################################################################################################################
#                                                                                                                          #
#                                         unRAID Server Preclear of disk 9LG121EE                                          #
#                                       Cycle 1 of 1, partition start on sector 64.                                        #
#                                                                                                                          #
#                                                                                                                          #
#   Step 1 of 5 - Pre-read verification:                                                  [24:06:51 @ 161 MB/s] SUCCESS    #
#   Step 2 of 5 - Zeroing the disk:                                                       [22:55:18 @ 169 MB/s] SUCCESS    #
#   Step 3 of 5 - Writing unRAID's Preclear signature:                                                          SUCCESS    #
#   Step 4 of 5 - Verifying unRAID's Preclear signature:                                                        SUCCESS    #
#   Step 5 of 5 - Post-Read verification:                                                 [24:05:19 @ 161 MB/s] SUCCESS    #
#                                                                                                                          #
#                                                                                                                          #
#                                                                                                                          #
#                                                                                                                          #
#                                                                                                                          #
#                                                                                                                          #
#                                                                                                                          #
############################################################################################################################
#                              Cycle elapsed time: 71:07:30 | Total elapsed time: 71:07:30                                 #
############################################################################################################################


############################################################################################################################
#                                                                                                                          #
#                                        S.M.A.R.T. Status (device type: default)                                          #
#                                                                                                                          #
#                                                                                                                          #
#   ATTRIBUTE                    INITIAL  CYCLE 1  STATUS                                                                  #
#   5-Reallocated_Sector_Ct      0        0        -                                                                       #
#   9-Power_On_Hours             4        75       Up 71                                                                   #
#   194-Temperature_Celsius      36       52       Up 16                                                                   #
#   196-Reallocated_Event_Count  0        0        -                                                                       #
#   197-Current_Pending_Sector   0        0        -                                                                       #
#   198-Offline_Uncorrectable    0        0        -                                                                       #
#   199-UDMA_CRC_Error_Count     0        0        -                                                                       #
#                                                                                                                          #
#                                                                                                                          #
#                                                                                                                          #
#                                                                                                                          #
#                                                                                                                          #
############################################################################################################################
#   SMART overall-health self-assessment test result: PASSED                                                               #
############################################################################################################################


--> ATTENTION: Please take a look into the SMART report above for drive health issues.

--> RESULT: Preclear Finished Successfully!.
 
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Disk 2:


 	
############################################################################################################################
#                                                                                                                          #
#                                         unRAID Server Preclear of disk QBG7431T                                          #
#                                       Cycle 1 of 1, partition start on sector 64.                                        #
#                                                                                                                          #
#                                                                                                                          #
#   Step 1 of 5 - Pre-read verification:                                                  [24:15:28 @ 160 MB/s] SUCCESS    #
#   Step 2 of 5 - Zeroing the disk:                                                       [23:04:04 @ 168 MB/s] SUCCESS    #
#   Step 3 of 5 - Writing unRAID's Preclear signature:                                                          SUCCESS    #
#   Step 4 of 5 - Verifying unRAID's Preclear signature:                                                        SUCCESS    #
#   Step 5 of 5 - Post-Read verification:                                                 [24:12:50 @ 160 MB/s] SUCCESS    #
#                                                                                                                          #
#                                                                                                                          #
#                                                                                                                          #
#                                                                                                                          #
#                                                                                                                          #
#                                                                                                                          #
#                                                                                                                          #
############################################################################################################################
#                              Cycle elapsed time: 71:32:24 | Total elapsed time: 71:32:25                                 #
############################################################################################################################


############################################################################################################################
#                                                                                                                          #
#                                        S.M.A.R.T. Status (device type: default)                                          #
#                                                                                                                          #
#                                                                                                                          #
#   ATTRIBUTE                    INITIAL  CYCLE 1  STATUS                                                                  #
#   5-Reallocated_Sector_Ct      0        0        -                                                                       #
#   9-Power_On_Hours             4        75       Up 71                                                                   #
#   194-Temperature_Celsius      34       45       Up 11                                                                   #
#   196-Reallocated_Event_Count  0        0        -                                                                       #
#   197-Current_Pending_Sector   0        0        -                                                                       #
#   198-Offline_Uncorrectable    0        0        -                                                                       #
#   199-UDMA_CRC_Error_Count     0        0        -                                                                       #
#                                                                                                                          #
#                                                                                                                          #
#                                                                                                                          #
#                                                                                                                          #
#                                                                                                                          #
############################################################################################################################
#   SMART overall-health self-assessment test result: PASSED                                                               #
############################################################################################################################


--> ATTENTION: Please take a look into the SMART report above for drive health issues.

--> RESULT: Preclear Finished Successfully!.
 
Copy to clipboard

 

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Hello guys!
I just finished successfully the preclear of two disks. However, I am unsure what the Status of the S.M.A.R.T section could mean. I got on both disks multiple status of 9-Power_On_Hours and 194-Temperature_Celsius. Googled it and tried to find something in the forum, however I still do not know if that is a "bad sign" or something related to early mortality. Does anybody know what this means an if it is problematic?
 
Thank you for your help!
 
Disk 1:
	#############################################################################################################################                                                                                                                          ##                                         unRAID Server Preclear of disk 9LG121EE                                          ##                                       Cycle 1 of 1, partition start on sector 64.                                        ##                                                                                                                          ##                                                                                                                          ##   Step 1 of 5 - Pre-read verification:                                                  [24:06:51 @ 161 MB/s] SUCCESS    ##   Step 2 of 5 - Zeroing the disk:                                                       [22:55:18 @ 169 MB/s] SUCCESS    ##   Step 3 of 5 - Writing unRAID's Preclear signature:                                                          SUCCESS    ##   Step 4 of 5 - Verifying unRAID's Preclear signature:                                                        SUCCESS    ##   Step 5 of 5 - Post-Read verification:                                                 [24:05:19 @ 161 MB/s] SUCCESS    ##                                                                                                                          ##                                                                                                                          ##                                                                                                                          ##                                                                                                                          ##                                                                                                                          ##                                                                                                                          ##                                                                                                                          ##############################################################################################################################                              Cycle elapsed time: 71:07:30 | Total elapsed time: 71:07:30                                 ##########################################################################################################################################################################################################################################################                                                                                                                          ##                                        S.M.A.R.T. Status (device type: default)                                          ##                                                                                                                          ##                                                                                                                          ##   ATTRIBUTE                    INITIAL  CYCLE 1  STATUS                                                                  ##   5-Reallocated_Sector_Ct      0        0        -                                                                       ##   9-Power_On_Hours             4        75       Up 71                                                                   ##   194-Temperature_Celsius      36       52       Up 16                                                                   ##   196-Reallocated_Event_Count  0        0        -                                                                       ##   197-Current_Pending_Sector   0        0        -                                                                       ##   198-Offline_Uncorrectable    0        0        -                                                                       ##   199-UDMA_CRC_Error_Count     0        0        -                                                                       ##                                                                                                                          ##                                                                                                                          ##                                                                                                                          ##                                                                                                                          ##                                                                                                                          ##############################################################################################################################   SMART overall-health self-assessment test result: PASSED                                                               #############################################################################################################################--> ATTENTION: Please take a look into the SMART report above for drive health issues.--> RESULT: Preclear Finished Successfully!.Copy to clipboard

Disk 2:

	#############################################################################################################################                                                                                                                          ##                                         unRAID Server Preclear of disk QBG7431T                                          ##                                       Cycle 1 of 1, partition start on sector 64.                                        ##                                                                                                                          ##                                                                                                                          ##   Step 1 of 5 - Pre-read verification:                                                  [24:15:28 @ 160 MB/s] SUCCESS    ##   Step 2 of 5 - Zeroing the disk:                                                       [23:04:04 @ 168 MB/s] SUCCESS    ##   Step 3 of 5 - Writing unRAID's Preclear signature:                                                          SUCCESS    ##   Step 4 of 5 - Verifying unRAID's Preclear signature:                                                        SUCCESS    ##   Step 5 of 5 - Post-Read verification:                                                 [24:12:50 @ 160 MB/s] SUCCESS    ##                                                                                                                          ##                                                                                                                          ##                                                                                                                          ##                                                                                                                          ##                                                                                                                          ##                                                                                                                          ##                                                                                                                          ##############################################################################################################################                              Cycle elapsed time: 71:32:24 | Total elapsed time: 71:32:25                                 ##########################################################################################################################################################################################################################################################                                                                                                                          ##                                        S.M.A.R.T. Status (device type: default)                                          ##                                                                                                                          ##                                                                                                                          ##   ATTRIBUTE                    INITIAL  CYCLE 1  STATUS                                                                  ##   5-Reallocated_Sector_Ct      0        0        -                                                                       ##   9-Power_On_Hours             4        75       Up 71                                                                   ##   194-Temperature_Celsius      34       45       Up 11                                                                   ##   196-Reallocated_Event_Count  0        0        -                                                                       ##   197-Current_Pending_Sector   0        0        -                                                                       ##   198-Offline_Uncorrectable    0        0        -                                                                       ##   199-UDMA_CRC_Error_Count     0        0        -                                                                       ##                                                                                                                          ##                                                                                                                          ##                                                                                                                          ##                                                                                                                          ##                                                                                                                          ##############################################################################################################################   SMART overall-health self-assessment test result: PASSED                                                               #############################################################################################################################--> ATTENTION: Please take a look into the SMART report above for drive health issues.--> RESULT: Preclear Finished Successfully!.Copy to clipboard

 

They are benign, I just left those there so I can see the comparison is working accordingly.

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Just wanted to leave a note here about pushing my preclear speed from 2 MB/s to 265 MB/s

 

tl;dr: beef up your CPU cause preclear uses openssl [0] which is very, very CPU heavy

OR modify the preclear script to not use AES256-CTR

 

100% CPU Usage: AMD E-350 -- 2 core, 2 thread, 1.6 GHz

 50% CPU Usage: Intel i5-6600 -- 4 core, 4 thread, 3.3 GHz

 

I was getting 100 MB/s on step 1 (pre-read), but only 2 MB/s on step 2 (erase). CPU was at 100% and top showed openssl as the top consumer. I dug into the logs and saw that preclear uses the output from openssl to generate random bits for the erase step. My media server is pretty weak, and was bottlenecking on CPU when running openssl. I moved over to another computer with a much faster CPU and saw my speeds go up by 100x.

 

If you don't have a spare computer lying around, you could modify the preclear script to use something faster.

 

The script uses the AES256-CTR cipher. AES acceleration is probably more important [1] here than raw cores or clock speed. The E-350 doesn't have AES acceleration, but the i5-6600 does. A potential alternative is using a non-AES cipher, like chacha20 [2]. 

 

The modified line in the script might look something like:

openssl_cmd="openssl enc -chacha20 -pass pass:'${pass}' -nosalt"

 

 

[0] https://github.com/gfjardim/unRAID-plugins/blob/b45bef5b26d9a3536043376f2b7d349922f35954/source/preclear.disk/script/preclear_disk.sh#L490

[1] https://blog.famzah.net/2015/06/26/openssh-ciphers-performance-benchmark-update-2015/

[2] https://crypto.stackexchange.com/a/52961

 

 

edit: Bonus! Was trying to understand why my write speed slows down from 265 MB/s to 150 MB/s. I eventually remembered that hard drives are spinning platters, and more bits are passing under the read/write head at the edges compared to the middle. Doing some quick math shows how big of a difference this makes.

 

# Assumes initial speeds of 265 MB/s,
# and platter goes all the way to 3.5 inches
# Formula --  speed = distance * (265 / 3.5)

Distance from Center (inches)  | 1.0 | 1.5 | 2.0 | 2.5 | 3.0 | 3.5 |
Read/Write Speed (MB/s)        |  75 | 113 | 151 | 189 | 227 | 265 |

 

Edited by WalkAbstract
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Should I add this disk to my array?

 

Just ran preclear on a 10TB WD Elements external drive and it reported:

 

#   ATTRIBUTE                    INITIAL  CYCLE 1  STATUS                                                                  #
#   5-Reallocated_Sector_Ct      0        1        Up 1                                                                    #

 

Should I return this drive, run another cycle to see if it increases, or add the drive to my array?

 

Thanks,

John

 

Edited by JDGJr
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I am having a very weird issue, every time that I restart the server Preclear plugin is gone and I need to reinstall it again. It installs ok without errors and once installed it works fine until the next restart that it will be wiped again.

It only happens with this plugin that I install using CA. Running Unraid 6.9.0-beta30.

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I am having a very weird issue, every time that I restart the server Preclear plugin is gone and I need to reinstall it again. It installs ok without errors and once installed it works fine until the next restart that it will be wiped again.

It only happens with this plugin that I install using CA. Running Unraid 6.9.0-beta30.

Have you updated nthe plugin recently?

 

 

If you can, please send me a PM with your Diagnostics file.

 

 

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There seems to be a bug or oversight where hot-plugged drives do not give a preclear icon/option in the MAIN tab but it is still possible to run it from the TOOLS tab. (I tried obvious things like refreshing the page.) Please fix.

 

Regarding the issue of this plugin disappearing after a reboot...

After I updated to latest version to fix this very issue, I still needed to reinstall the plugin after a reboot -- at least twice more.

(I should send you a diagnostics file again.)

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OK, I've used the Preclear plugin successfully to preclear a 300GB Maxtor drive. The precleared drive shows up under Unassigned devices. There's a button to format it, but it's grey and has lost its link. Below is a list of Missing drives and the Maxtor appears there.

 

Can anyone tell me what's going on here?

 

-- 

Chris

Precleared and Missing.png

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OK, I've used the Preclear plugin successfully to preclear a 300GB Maxtor drive. The precleared drive shows up under Unassigned devices. There's a button to format it, but it's grey and has lost its link. Below is a list of Missing drives and the Maxtor appears there.
 
Can anyone tell me what's going on here?
 
-- 
Chris
1089953172_PreclearedandMissing.png.59596fb4cfb41f8967de30c59f334756.png
You have to click on that red X to clean your preclear session to format your drives.

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Thanks for getting back to me.

Ok, I've done what you suggested. The red X disappears and I've refreshed the browser page. But there's no change. The format button is still greyed out and the drive still appears as both unassigned and missing.

I intended to add the drive to the array.

--
Chris72eef3837b358670bb6ecb389be46969.jpg

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