Removed Cache drive and the user share set to prefer cache is missing.

[mbeh4678]

I have a three drive system (1 parity HDD, 1 storage HDD, 1 cache SSD). I needed to use the cache drive for antother project, so I removed the cache drive from the array and then unplugged it from the system. But after rebooting the array, the share (General) with most of my data is now missing. the configuration for the share is still on the boot drive. I have done a parity check but with writes disabled. Ill include both the config of the share and a diagnostics zip. Is there a way that I can rebuild the share from parity? or is this just a configuration error? Any help is appreciated.

General.cfg tower-diagnostics-20230315-1005.zip

[JorgeB]

Do you mean that share was on cache? If yes you must first move the data to the array before removing the cache drive.

[mbeh4678]

Well I guess it depends on how the cache works. There was lots of data in the array even before I added the cache drive, so unless setting the share to prefer cache takes the data out of the array and onto the cache, there should still be the original data in the array.

 

[JorgeB]

49 minutes ago, mbeh4678 said:

so unless setting the share to prefer cache takes the data out of the array and onto the cache

Yes, that's exactly what cache=prefer does, every time the mover runs it moves any data on that share from array to cache.

[mbeh4678]

And when it does it removes it from parity as well? Sorry if I'm going in circles, I just havent worked with this system much. 

[Frank1940]

1 minute ago, mbeh4678 said:

And when it does it removes it from parity as well? Sorry if I'm going in circles, I just havent worked with this system much. 

It was never in "Parity".   See here for how parity works.  It a simple mathematical operation performed on every byte of all the data disks in the Array.  The result of this operation is written to corresponding byte on the parity disk.  The cache disk is not a part of the Array.  See here for a description of parity:

 

        https://wiki.unraid.net/Manual/Overview#Parity-Protected_Array

[JonathanM]

To add to Frank's excellent answer, I'll give you an analog that works the same way. Take a RAID1 volume with 2 members. Delete a file from the RAID1 set. The file gets removed from both members at the same time, to keep them in sync. Parity is the same concept, just expanded to cover all the parity array members. If parity is in sync, any one (or two if you have dual parity) drives can be removed and the parity bits will fill in the blanks and allow you to work with them just like they still were there, and when you assign a physical disk back to the slot, it will rebuild that emulated disk back to the physical drive to keep parity in sync. Just like how you can seamlessly continue to work with a degraded 2 member RAID1 volume that is missing a disk, and when you add a disk back it gets synced back in to match what was done on the degraded volume.

[trurl]

5 hours ago, mbeh4678 said:

needed to use the cache drive for antother project

Have you done anything with that drive yet? If it still has your Unraid data on it we can help you get that data onto the array.

 

[mbeh4678]

I had already formatted the cache drive sadly. I guess I was mistaken for how the cache was setup. I thought that cache was used as the ingest point and everything was later moved to the array, didn't think it would actually take data off of the array that was already there.

 

[itimpi]

12 minutes ago, mbeh4678 said:

point and everything was later moved to the array, didn't think it would actually take data off of the array that was already there.

It would have done that if you had the correct Use Cache=Yes setting.   Unfortunately you configured it do exactly the opposite.    The help built into the GUI for the Use Cache setting might have helped explain how the setting option interacts with mover.