Two ideas to (immensely) help in a mid-recovery situation.

[NLS]

I have this post made:

 

 

...where it leads me to think of two things missing currently from UNRAID that would be very nice to be implemented (and able to be used directly from the GUI).

 

1) Actually implement a "read-only and bring online as is" mode. So if disks (more than parity recover ability) are missing, their data will be missing (as they cannot be emulated), but parity is not touched, pending the disks actually coming back later.
This feature, would be great for temporary use when actually bringing even a limited server online, is critical.
Cache disk can remain read/write (so normally containers and VMs will work - if needed images are in cache as is the default) but no mover will run as the actual array remains read-only.
 

2) Make it possible through the GUI to actually switch a disk missing with another, trusting it has the same content (bit for bit) as the missing one. For cases of replaced controllers, that normally change the disk identification.
Should be an "expert" option, with all the "are you sure you know what you are doing" in place.
In the thread above seems there is a workaround to this already?
 

[trurl]

3 hours ago, NLS said:

Should be an "expert" option, with all the "are you sure you know what you are doing" in place.
In the thread above seems there is a workaround to this already?

I think it's better to work through each step of the workaround with guidance, there are possible complications such as unmountable filesystems. Most Unraid users don't really even seem to know how parity works and I wouldn't trust them to know when to try this "expert" option if it were available.

[ChatNoir]

4 hours ago, NLS said:

Should be an "expert" option, with all the "are you sure you know what you are doing" in place.

When people have a issue, they start to panic and do things they think will help. Reading warning is optional.

 

The best example is formatting an unmountable drive in the Array.

There is a big pop up warning users not to format a drive in the Array, it explain that format is not part of rebuild.

 

And we still have at least one user a week that formatted a drive and expected the rebuild to be OK.

 

Warnings are not a reliable solution.

[NLS]

Maybe you guys are right.

 

That said, the first idea is super helpful and I really hope it gets added.
(and is not destructive - even if array is fully normal, the only difference the user would notice is that the shares are read only)

It is actually an in-between of normal operation and maintenance mode.

Maintenance mode doesn't mount any disk or cache.
This one would mount every disk available in array (and start it even with disks and data missing), but read-only (so that parity is not killed), so that people can access important (remaining) data AND cache (and normally domains, system and appdata - if they still reside in cache) read/write so that VMs and containers can start.
 

[trurl]

18 minutes ago, NLS said:

cache (and normally domains, system and appdata - if they still reside in cache) read/write so that VMs and containers can start.

You might be surprised how many have these shares at least partially on the array, either because they set them to be moved, because they overflowed, or because they got recreated on the array due to missing cache. I probably see this in diagnostics every day.

[NLS]

15 hours ago, trurl said:

You might be surprised how many have these shares at least partially on the array, either because they set them to be moved, because they overflowed, or because they got recreated on the array due to missing cache. I probably see this in diagnostics every day.

 

I know - I even have a couple of test VMs on the array on purpose.

This won't "hurt" though, just those will fail if started.
It is a very useful function to have for people that need it.
Ability to work in production environment even partially is very important.

 

[NLS]

Experts in the room:

Is it possible to achieve #1 partially, by going to maintenance mode and then using unassigned devices to mount cache?

(and not mount the other disks at all)

Will I be able to then start some containers and vms?

Also I think UD also allows to mount as read-only. Can I use that to access my remaining data without affecting parity?

 

[JorgeB]

43 minutes ago, NLS said:

Is it possible to achieve #1 partially, by going to maintenance mode and then using unassigned devices to mount cache?

Not practical, you'd need to unassign cache to be able to mount with UD and even worse the configured paths would not be the same, if you had for example /mnt/cache/appdata or /mnt/user/appdata you'd need to change it to /mnt/disks/UD_label/appdata

 

44 minutes ago, NLS said:

Also I think UD also allows to mount as read-only. Can I use that to access my remaining data without affecting parity?

It does, you'd need to unassign the disk but would be able to mount it read-only with UD, of course there are no shares, it would be disk by disk.

[NLS]

OK clear.

 

I still can only hope #1 gets "properly" implemented for disaster situations some time.

In my case, I don't want to destroy my parity yet, as it is yet undetermined if the disk will recover, cloned or what.

 

Edited September 21, 2022 by NLS