SHR to SHR2 migration and 1 or 2 empty disk rules

[sarhoshamiral]

I have DS1522+ (5 bay) with 4 disks. 2 x 18TB and 2 x 20TB, they are all in a single SHR1 volume right now. I am considering moving to SHR2 by buying a new disk but this note is fairly confusing to understand and Synology hasn't provided any examples:

• In a RAID array comprising three or more drives, the capacity of the two largest drives is larger than that of the other drives.

The way I read this is that I will need 2 empty drives regardless because I have 2 x 20TB which are larger then other 2 x 18? Is that correct or if I get a new 20TB drive, will I be fine to migrate to SHR2 with that new drive alone?

If I need 2 empty drives and have enough capacity, would it be possible to deactivate and remove one of the drives from current volume and then expand it to SHR2 with now 2 empty drives?

Thanks!

 

[Rusty]

Welcome to the forum.

If I need 2 empty drives and have enough capacity, would it be possible to deactivate and remove one of the drives from current volume and then expand it to SHR2 with now 2 empty drives?

Removing the drives will place you in a degraded mode. That means you will first have to repair it with new drives before you can start to convert the array.

Is that correct or if I get a new 20TB drive, will I be fine to migrate to SHR2 with that new drive alone?

Correct.

SHR-1 to SHR-2 will require a new drive in order to expand as per documentation. Change the RAID Type of a Storage Pool | DSM - Synology Knowledge Center

 

[sarhoshamiral]

Welcome to the forum.


Removing the drives will place you in a degraded mode. That means you will first have to repair it with new drives before you can start to convert the array.


Correct.

SHR-1 to SHR-2 will require a new drive in order to expand as per documentation. Change the RAID Type of a Storage Pool | DSM - Synology Knowledge Center

Not only a new drive but 2 new drives in my case it looks like due to different drive sizes. I did try choosing migrating to SHR2 in storage manager and that's what the message said. And given that I can't make the array smaller by removing a drive, my only option is to first replace 18TB drives with 20TB ones.

 

[Rusty]

Another option is to backup the critical data, destroy the array and start fresh with SHR2

 

[Telos]

destroy the array and start fresh with SHR2

... knowing that any backup short of a "full system backup" is incomplete.