[Resolved - bug reported] Scheduled parity check interrupted disk rebuild.

[FreeMan]

I believe this is a bug, but thought I'd first post here in General Support, for confirmation.

 

I had to replace a disk and I kicked off the disk rebuild yesterday. My server is suddenly having overheating issues like never before, so Parity Check Tuning has been pausing the disk rebuild to allow the drives to cool back down. Therefore, the rebuild has been going very slowly (it runs for about 30-45 minutes, the drive overheats, it pauses for 15-20 minutes. Lather. Rinse. Repeat.) When I went to bed last night, I snuck a quick peak and it was about 55% complete on the disk rebuild. (Yes, I'll be looking into the overheating as soon as I've got the disk rebuilt. In the meantime, I've got extra fans blowing, though I'm not sure it's helping a lot...)

 

When I woke up this morning and checked on the rebuild, I was quite shocked to find that it was in the high single-digit percentage (7-9% somewhere). It seems that my regularly scheduled monthly parity check kicked off at about 3:30 this morning.

 

The parity check history does not show anything from the data rebuild (TBH, I don't know if it should):

 

And, more importantly, the drive is still showing emulated:

I'd imagine that whatever happened will show up here:

nas-diagnostics-20210701-0749.zip

 

If this is indeed a bug, is it possible to just move this to the Bug Reports section? If not, I'll retype it all.

Edited July 1, 2021 by FreeMan

[JorgeB]

It's still rebuilding the disk but it started over because of the scheduled check, not sure this is ab bug or plugin related, you'd first need to see if the same happens without the plugin.

[FreeMan]

Sigh. OK.

 

Before I do anything else, I need to get this disk rebuilt. Then I need to get the cooling sorted.

 

If I remember, I'll get back to checking this out after those are all sorted out.

[itimpi]

Sounds like a potential bug if the parity check is started while a rebuild is in progress     The Parity Check Tuning Plugin does nothing that you could not simulate manually by using the Pause/Resume buttons on the Main tab at appropriate times so as such it should not be the plugin that causes this issue although the plugin might make it more likely by extending the time for the rebuild to complete.   I can see the plugin getting a little confused if a rebuild suddenly changes to a parity check mid-flight but I think it should handle this but i need to check this is correct.

 

I will have to see if I can recreate this exact sequence of events and if necessary raise an appropriate bug report to get clarity on what is expected behaviour.

 

You do not normally get an entry added to the Parity History for a rebuild (or clear).   If it is thought it would be of use I could enhance the Parity Check Tuning plugin to add such entries.

[FreeMan]

Thanks,@itimpi.

Not trying to pick on you with these PCT reports lately, I promise! I've discovered that I'm pretty good at finding bugs in other's code, not so good at finding them in my own. [emoji53]

Frankly, if it weren't for PCT automatically pausing the rebuild, I may well have cooked a drive by now, so I don't really mind all that much. I have no idea why it's running so hot after installing this one additional drive. Fixing that is my next highest priority.

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[FreeMan]

it adds nothing to the discussion, but it's quite sad:

 

(Wow, sorry that's so BIG!)

 

Those are the Pushover notices from when it reset. I was wrong in my initial report - the Parity Check is scheduled for 00:30, not 03:30 on the first of the month.

 

There is a minor issue of the extra "%" sign in there, but I think this is the first time I've ever noticed, so it's definitely a minor issue.

 

 

[itimpi]

26 minutes ago, FreeMan said:

There is a minor issue of the extra "%" sign in there, but I think this is the first time I've ever noticed, so it's definitely a minor issue.

That IS a PCT bug but as you say cosmetic.   Still it will get fixed  

Happy to have any reports on PCT issues as that is the way issues get identified and fixed.    What I am trying to avoid is simple dismissing of a problem report if the PCT plugin is installed when the actual issue is probably something else.

[JorgeB]

Did a quick test without the plugin installed, if a rebuild is running at the time scheduled for a parity check it will attempt to start one but since the rebuild is already running nothing happens, on the other hand if the rebuild is paused, I did it manually but it would be the same if paused by the plugin, then it re-starts the current rebuild from the beginning, so it's an Unraid bug, it's a minor one and one that won't affect many users but it might still be worth reporting.

[FreeMan]

Did a quick test without the plugin installed, if a rebuild is running at the time scheduled for a parity check it will attempt to start one but since the rebuild is already running nothing happens, on the other hand if the rebuild is paused, I did it manually but it would be the same if paused by the plugin, then it re-starts the current rebuild from the beginning, so it's an Unraid bug, it's a minor one and one that won't affect many users but it might still be worth reporting.

Unless this can be moved to the bug thread, I'll post an issue later today.

Thanks for duplicating it.

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[JorgeB]

13 minutes ago, FreeMan said:

Unless this can be moved to the bug thread

We can't, it's a separate database, there's a copy option but never used it before and not sure how it works.

[FreeMan]

We can't, it's a separate database, there's a copy option but never used it before and not sure how it works.

Fair enough

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[FreeMan]

5 hours ago, itimpi said:

If it is thought it would be of use I could enhance the Parity Check Tuning plugin to add such entries.

I think it would be useful if disk rebuilds were logged in the Parity Check history. I think it would be even better if they could be kept in a separate category, but that's probably not possible, so a simple entry there would be fantastic.

 

Also, bug report filed, so I'm marking this one "resolved", since it seems nothing else can be done from this end.