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I have two LinkStations (LS220 and LS421)  Each has 2× 2TB HDDs in RAID 1.  If/when one drive fails, can it be replaced in the RAID by a larger drive?  If yes, once the RAID1 is rebuilt, can I then replace the other drive with a similarly larger one, and increase the size of the RAID 1 Array?

Hi it appears I have the same/similar query with a LS420D - just wondering if you had any response?

One of my 2TB drives in RAID1 failed and I replaced it with a 4TB (understanding that in this arrangement it would be limited in storage capacity by the smaller original HDD) - I've been trawling through the forums to look for advice on whether swapping out the other (original) 2TB drive with another 4TB drive would be an effective way of simply creating a 4TB RAID1 Array... or am I being naïve?

Cheers

The answer is somewhere between "no" and "only with some risky command line work"

Even if you replace both disks with bigger drives the size of the array stays the same because the size is part of the metadata of the array. It is supposedly possible to delete the array metadata and then recreate it as a larger array, grow the filesystem etc.

You wouldn't be able to do any of that from the web interface and you might need to tweak the mdadm.conf etc if it changes the UUID.... I've never tried it myself.

Source:
https://www.tjansson.dk/2015/12/growing-a-mdadm-raid-by-replacing-disks/

Quote from: mc_cello on February 16, 2022, 07:57:49 AM
Hi it appears I have the same/similar query with a LS420D - just wondering if you had any response?

One of my 2TB drives in RAID1 failed and I replaced it with a 4TB (understanding that in this arrangement it would be limited in storage capacity by the smaller original HDD) - I've been trawling through the forums to look for advice on whether swapping out the other (original) 2TB drive with another 4TB drive would be an effective way of simply creating a 4TB RAID1 Array... or am I being naïve?

Cheers

You can change the other 2TB disk to a 4TB but it will still show the capacity size of the original RAID (2TB), not unitl the RAID is deleted and recreated will you see the new increased capacity.