Shrinking an array: New Config and Unassign vs Unassign

[ldrax]

Referring to this guide here: https://wiki.unraid.net/Shrink_array
I wonder why must we do New Config -> Retain current -> Unassign, rather than just Unassign directly?

I'm about to retire 4 disks (all filled with data needed to be transferred first to other build) from my array, I'm trying to weigh what's the most effective (and safest, of course) way to do it.

 

[JorgeB]

2 hours ago, ldrax said:

I wonder why must we do New Config -> Retain current -> Unassign, rather than just Unassign directly?

Because if you just unassign Unraid will consider there is one or more missing disks.

[ldrax]

I see. So the New Config -> Retain Current is completely safe then? My hands would tremble in clicking new config.
This got me thinking, would this New Config work with any existing drives from other UNRAID builds, then? In an extreme case, for example, take any number our disks out of a few different unraid builds, and bunch them together in a new build, and do a new config, then start array, parity will rebuild. This without losing existing data?

 

[JorgeB]

It's safe as in no data on the disks assigned as data drives will be touched, including if you use disks from a different Unraid server, main things to keep in mind are never assign a data disk to a parity slot by mistake and the array will be unprotected until the parity sync finishes.

[ldrax]

That's great to know! Thanks Johnnie Black!