Emulated Rebuild After Temporarily Removing Parity Drive - Need Guidance

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Hello Unraid community,


I hope you're all doing well. I recently encountered a situation with my Unraid server that has left me seeking some guidance. Here's the scenario:


I needed to perform a drive clone operation (ddrescue) using a spare SATA port, so I temporarily removed my Parity 2 drive to free up the port.

After completing the clone operation, I reconnected the same Parity 2 drive to its original SATA port.

Upon powering up my Unraid server with the Parity 2 drive restored, I noticed that it appeared with a blue icon in the Unraid webGUI.

The blue icon seems to indicate that the drive is being emulated or that some sort of background operation is taking place. However, I'm not entirely sure why this is happening, especially since I'm using the same drive that was previously part of my array.

My questions are as follows:

Is it normal for a Parity drive to go through an emulated rebuild process when it's temporarily removed and then reconnected to the same port?

The estimated time for this emulated rebuild is quite long, around 19 hours. Is such a lengthy rebuild necessary for the same drive, or is there a way to expedite this process?

Should I be concerned about data integrity during this process, or is there anything specific I should check or monitor?

I'd greatly appreciate any insights or advice from the community regarding this situation. I want to ensure that my server is operating smoothly and that my data remains safe.

Thank you in advance for your help!

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11 hours ago, Squid said:

Did you start the array with Parity 2 removed?  If you did, then it's natural that it has to rebuild the contents of Parity 2 when you've re-added it.


Darn, I asked too many questions.  I was hoping the core question (how to expedite the process) would garner answers.


Or more specifically, if I want to run ddrescue to clone from drive to drive and I have only 1 spare SATA connection available (because the array is taking up all the other SATA connections in the unRAID PC) how do I free up a SATA port and avoid later paying the cost of a long parity re-build after?  (Background: ddrescue cloning requires a source and a destination -- that's two SATA ports!)   Instead of parity 2 (which I removed because I thought it was redundant) should I swap out the fullest data drive (because it would be the least likely to be added to) and then hope restoring the full data drive back to the array won't initiate a full parity rebuild?  (Ohhhhh, second guessing how unRAID is gonna react is so fraught with doubt.. I just wanna clone a drive.)


Edited by oh-tomo
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