Feature Request: Better indication of Parity Check + correction vs. Parity Check


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TLDR:

1. Clearer definition of Parity Check + "write corrections to parity disk" versus Parity check (read only), possibly with new naming

2. Documentation or a configurable setting that indicates whether a hard power off and the subsequent parity check on reboot is the read only or the read-write version

3. Parity History popup indicating status of "write corrections to parity disk" in previous runs

 

___________

I searched through the forums but couldn't find much on this.

 

Basically, when we manually start a Parity check, there is an option to "Write corrections to parity." Without it, the Parity Check will run but not update the Parity drive with any discrepancies between the parity data and the data disks. That means that a Parity Check without the checkbox is more a Parity validation/check.

 

When the checkbox is ticked though, the Parity drive will be rewritten in the event of any discrepancy between the data disks and the parity disks.

 

For ease of reference, I'd love to see these terms clarified. Something that still holds the reverence of a full data read, but something that reflects that Parity disk data will be changed. I think Parity Check is still a fine term to be used for the read and diff to confirm there are no errors, and Rebuild is already taken in the Unraid universe when we need to get back the contents of a disk. Could a new term such as Parity Update or Parity Recompute or Parity Correction be used for instances of Parity runs where the checkbox is enabled?

 

One other thing is that I'm not clear on what type of Parity Check is done on a power loss. Parity Check will start regardless at the next boot, but there's no setting or indication to make this behavior follow one option or the other. 

 

 

Finally, I wonder if it would be possible in the Parity history popup to have a new column that indicates whether or not the Parity disk was corrected to match the data disks. Looking at the history in its current form (or logs or anything else as far as I'm aware) there's no way to know what previous runs were configured as: with or without the "write corrections option"

I hope this makes sense and am happy to revise or provide any more detail to submit this feature request for consideration! Alternatively, If I'm missing a feature already present in Unraid that would help me distinguish, please point me towards it. As mentioned I did a scan of the forums after coming up blank in the Web UI, but I could have missed it. 

 

Edited by kubed_zero
moved TLDR to top
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2 hours ago, kubed_zero said:

One other thing is that I'm not clear on what type of Parity Check is done on a power loss. Parity Check will start regardless at the next boot, but there's no setting or indication to make this behavior follow one option or the other. 

It's non correcting.

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  • 5 months later...
On 7/26/2020 at 12:14 AM, kubed_zero said:

Could a new term such as Parity Update or Parity Recompute or Parity Correction be used for instances of Parity runs where the checkbox is enabled?

 

IMHO, this is a wonderful suggestion. I would say `Parity Update` is the best option - short and intuitively understandable.

 

Also, I would like to propose that Parity Check and Parity Update would be split into separate buttons in the UI.

Furthermore, it would be nice if:

  • Parity Update button would be disabled by default. As much as I understand, it is recommended to always run a Parity Check not and Update, at least according to wiki. Notice, how much easier it is to say Check and Update, instead of Check and Check without writing... yada...yada...yada... 😉
  • When and only when parity errors have been found, the Update button is enabled.
  • And the most useful feature would be, if unRAID would keep the log of error block, where errors have just been found during the Parity Check. Then, running the Update, it could use that log to read and update only the blocks, that had errors. Imagine 200TB+ array with 1 parity error... 😉

IMHO, the result - way more intuitive and considerably faster way to deal with parity checks and errors. 👍

 

On 7/26/2020 at 12:14 AM, kubed_zero said:

Finally, I wonder if it would be possible in the Parity history popup to have a new column that indicates whether or not the Parity disk was corrected to match the data disks. Looking at the history in its current form (or logs or anything else as far as I'm aware) there's no way to know what previous runs were configured as: with or without the "write corrections option"

 

A column, where it clearly states the action taken - Parity Check or Parity Update. That'd be perfect.

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2 hours ago, shEiD said:

Also, I would like to propose that Parity Check and Parity Update would be split into separate buttons in the UI.

This is effectively there already.    You get parity Update if the checkbox to write corrections to parity is checked, and Parity Check if it is not.

 

if you have the Parity Check Tuning plug-in installed then you get some extra information recorded in the History file including what type of Check an entry refers to.

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