Hardware systems like traditional RAID, or modern software systems like ZFS, btrfs, etc. are used for redundancy (and performance) of the storage of data. Whenever a drive dies in one of these redundant systems the process of writing data to it is called resilvering. Where did this phrase come from?
I've looked around for any sort of evidence. But the only thing I've been able to find is this dubious blog post: https://lonesysadmin.net/2012/03/23/why-is-it-called-resilvering/
Q: Why do some people refer to the process of remirroring or rebuilding a RAID 1 drive set as “resilvering?”
A: Antique mirrors (the reflective kind you hang on a wall, or are in your bathroom) used silver (Ag) for the reflective coating, below the glass. Over time that silver would get tarnished and/or damaged, so you’d restore them by re-silvering them. I’m sure you’ve all seen this, where an old mirror has streaks in it but they’re below the glass. When your RAID 1 mirror set gets “tarnished” you resilver it and it’s shiny & new again. You can rebuild a RAID 5 array but you resilver a mirror. :)
With no real evidence. It might be correct. But I'd love to see some evidence or even confirmation/a different explanation from a more authoritative source.