[6.11.5] Can a rebuild be safely interrupted? (Solved)

[JazzHands]

It may sound like a bit of an oxymoronic question, but I'd like to swap out an older drive with a new higher capacity one in my single parity disk protected array. Rebuild will take about 16 hours, but it will be interrupted with a power outage. Server has a UPS and shuts down gracefully. 

 

Will a graceful shut down and start up cause a rebuild to restart from the beginning? Or can it resume?

Edited January 6, 2023 by JazzHands
Solved

[JorgeB]

10 minutes ago, JazzHands said:

Will a graceful shut down and start up cause a rebuild to restart from the beginning?

This

[JazzHands]

6 minutes ago, JorgeB said:

This

Sorry, I didn't understand, is that a yes?

[JorgeB]

Yes.

[Kilrah]

Since you asked 2 questions in one line...

 

Rebuild can't be interrupted without starting over from the beginning. So wait until after your power cut to make the swap.

[JazzHands]

3 minutes ago, Kilrah said:

Since you asked 2 questions in one line...

 

Rebuild can't be interrupted without starting over from the beginning. So wait until after your power cut to make the swap.

 

Power cuts happen on average every 8-12 hours and have been for 6 months (South Africa). My UPS only provides about 40 minutes of runtime during a parity check, so I assume it's about the same when rebuilding. 

 

I'll have to make a plan to find a window long enough for a rebuild.

[itimpi]

If you install the Parity Check Tuning plugin then it has an option to restart array operations from last point reached on next boot as long as your UPS allows your Unraid server to do a tidy shutdown.

[JazzHands]

On 1/4/2023 at 12:24 AM, itimpi said:

If you install the Parity Check Tuning plugin then it has an option to restart array operations from last point reached on next boot as long as your UPS allows your Unraid server to do a tidy shutdown.

 

This is working. The only downside is that when power is restored, the array needs to be manually started. Started about 2200 last night, had a power outage at 0200-0430. Array wasn't started automatically. Manually starting it caused the rebuild to resume. 5 hours to go, not counting another 2 hour outage. 

[itimpi]

5 minutes ago, JazzHands said:

 

This is working. The only downside is that when power is restored, the array needs to be manually started. Started about 2200 last night, had a power outage at 0200-0430. Array wasn't started automatically. Manually starting it caused the rebuild to resume. 5 hours to go, not counting another 2 hour outage. 

Not sure that I can find a way around the array not auto-starting although I will put it on my list of things to look at.  I think it is a change in behaviour from earlier releases of Unraid (but I am not sure), and regardless it looks like it is the behaviour of the current release and probably therefore the forthcoming 6.12 release.  I would need to research both how I can tell the reason that Unraid is not honouring an auto-start, and then also how to start the array if everything looks OK so it may not be that easy to work around.

[JazzHands]

Do you know if there is a notification if an array isn't auto-started? I have all notifications enabled, but don't recall seeing any. 

[itimpi]

4 minutes ago, JazzHands said:

Do you know if there is a notification if an array isn't auto-started? I have all notifications enabled, but don't recall seeing any. 

Not that I know off.

 

I think it is side-effect of the previous array operation being terminated early and Unraid deciding not to automatically restart it because of that.   The core Unraid level will not realise the plugin can resume from the point previously reached.