preclear, do we still do it ?

[loady]

I have a drive that is constantly disabled, i have done an extended SMART test and the unallocated sector count is going up and up, I have ordered an new 3tb WD red, I have been using unraid for over seven years and this is my first drive failure, as I do not have any problems using unraid and have updated over the years, I want to ask, is pre clearing still a job to be done prior to rebuilding data or does it get done in the background automatically, previously, all my current drives were pre cleared utilising MC and screen. Is it even necessary to preclear a drive, esp a WD red ? 

[binhex]

I have a drive that is constantly disabled, i have done an extended SMART test and the unallocated sector count is going up and up, I have ordered an new 3tb WD red, I have been using unraid for over seven years and this is my first drive failure, as I do not have any problems using unraid and have updated over the years, I want to ask, is pre clearing still a job to be done prior to rebuilding data or does it get done in the background automatically, previously, all my current drives were pre cleared utilising MC and screen. Is it even necessary to preclear a drive, esp a WD red ? 

Firstly it's not necessary to preclear a drive anymore and thus you do not need to run the preclear script however I personally would not add a drive without running the preclear script, the reason being that it stress tests the drive and ensures that the drive is sound before adding to the array

Sent from my EML-L29 using Tapatalk

[loady]

Yes I understand, however, I bought this WD red because of its warranty, if a preclear is going to buckle it I would suggest that is going to buckle within the warranty period, its 3TB...I dont think I can wait a day for it to preclear. I am going to do the same with any future drive failures (replace with WD red), im sure im due for more, I have a couple of drives in my array that dont get good write ups. Ideally I wanted to get a 4tb WD red and swap out the current 3tb parity, again, this was a time issue for me as I use my server remotely from a former address which I only visit twice a week.

 

Just out of curiosity, why dont we have to preclear anymore ?

[binhex]

10 minutes ago, loady said:

if a preclear is going to buckle it I would suggest that is going to buckle within the warranty period

this is a personal choice, for me i want to know the drive is ok before rebuilding/adding data to it (think about failed writes), that way i can confidently sell the old drive (assuming its a replacement) once the rebuild has completed. Sending a failed drive back to WD sooner rather than later also sounds like a good idea to me, but each to their own :-).

 

14 minutes ago, loady said:

Just out of curiosity, why dont we have to preclear anymore ?

originally the preclear script was designed to do one thing, preclear drives in readiness to be added to the array, this was deemed a good idea as it used to be the case that adding a new drive meant unraid had to preclear it, and this meant the whole array would be offline until that preclear ended, taking many hours, not good for the WAF!. The script then got enhanced to do other stuff as well, such as stress testing of the drive using various linux utils. 

 

roll forward in time and preclearing a drive via unraid now is done in the background, allowing the array to carry on working and thus no down time, meaning no need to preclear, however the need to stress test a drive is still present (imho) and thus the preclear script lives on.

[whipdancer]

What binhex said. 

I still preclear my drives before adding them to the array.

Besides, if the drive in question is already failing/disabled/<whatever>, what difference is a day going to make for the preclear?

[loady]

Its odd, the drive that failed, i put in a usb caddy and formatted and it seems to work ok, obviously Unraid knows things about it that windows doesnt give a monkeys for

[JonathanM]

2 minutes ago, loady said:

Its odd, the drive that failed, i put in a usb caddy and formatted and it seems to work ok, obviously Unraid knows things about it that windows doesnt give a monkeys for

Yeah, windows will use a failed drive just fine as long as the data portion that is in use doesn't spit back garbage. Many times a windows update will force windows to use a part of the drive never touched before, and the computer will crash and the user blames the update.

 

Unraid requires the entire drive to be perfect, there is no such thing as unused space in the unraid parity protection model. Even drives with no data, freshly formatted are entirely used for parity.

[loady]

thats ok i guess then, i can use it as a mule for transporting files between site

[trurl]

On 4/24/2019 at 4:20 AM, loady said:

im sure im due for more

Do you have any SMART warnings on the Dashboard?

[loady]

not now i replaced the drive, i had done a extended smart with the one that was disabled and UNraid pretty much said throw it in the bin !...the unallocated sector count was not good and was rising