Add a third HDD to a Raid 1?

[Alby87]

Hi!

Recentely I heard that my two HDD from WD (Red) are from a batch that is know to be prone to failure. So I just got a Seagate with the same size (4 TB) and wanted to add it to my RAID 1. When trying to add to storage 1 it seems I can not add it. Is RAID 1 blocked to just twin HDD? If no, please tell me where I should add the thrid HDD to RAID1

If yes, what's the cleanest why to make one of the twins my new seagate and make the other WDD a single hard disk volume?

Im using F4-421 with the latest TOS6.0 installed.

Thanks!

[TMzethar]

The number of members in RAID1 is initially determined. If you use two disks for RAID1, it will always be two disks. Due to the redundancy mechanism of RAID1, you can remove 1 abnormal WD disk and repair the RAID1 with a new Seagate disk.
https://toshelp.terra-master.com/web/#/cn/desktop (How to Repair RAID?)
viewtopic.php?t=1545

[Alby87]

Perfect. Now the plain is using one WD + Seagate as Volume1, and the other WD as a totally disposable single disk Volume2 (that, if lost, absolutely no damage, instead of Volume1, that is important and also backuped online)

1) Rebuild RAID1 with one WD and Seagate.
2) When completed, restart NAS without any hdd, insert the now orphaned WD, reset it wiping hard disk and superblock
3) Insert all hard disks
4) Create Volume2 on WD

It sounds, doesn't it?

[TMzethar]

You mentioned that both of your WD drives are abnormal models. I had assumed you would prepare two Seagate disks to replace them one by one. If you only replace one, there may still be hidden risks remaining.

[Alby87]

Ah, yes, but waiting some time for buying the second Seagate: I will use the solution above for some days,then I will change also the first WD and pair with the second WD. So the WDs will have disposable files, the Seagates unrepleceable files.

[Herewerare2024]

Could also use the removed HDD as a hot spare...