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Reusing RAID 1 disk to backup

amtrakuk1
Aspirant

Reusing RAID 1 disk to backup

Hi there,

 

I have a Readynas 104 with 2 x 3TB disks running as RAID 1.  I had to replace one of the disks as it was flaging as having bad sectors.   I have since replaced the disk and everything is fine.   I now want to re-use the removed disk as a very temp backup however if i drop it into a caddy and connect it to a laptop to clear any data the disk only reports the available 800GB free space. 

 

I have tried gpart trying to locate the RAID information to clear but unable to.   Anyone know how I can clear the disk to allow me to recover the lost space.   Pref using Ubuntu.

 

Thanks

Model: RN10421D|ReadyNAS 100 Series 4- Bay
Message 1 of 10

Accepted Solutions
StephenB
Guru

Re: Reusing RAID 1 disk to backup


@amtrakuk1 wrote:

The mystery is why a 3TB drive only reports 1 partition of 800 GB unused space.   How can I access the "hidden" c2.8 TB used space?

 

 


I think that's because your SATA->USB adapter is limited to a max size of 2 TB drives.  If I am right, you need a different adapter - nothing else will work.

 

View solution in original post

Message 4 of 10

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StephenB
Guru

Re: Reusing RAID 1 disk to backup


@amtrakuk1 wrote:

if i drop it into a caddy and connect it to a laptop to clear any data the disk only reports the available 800GB free space. 

 

 


Are you really meaning 800 GB free space or do you mean the total size is 800 GB.  I am guessing total size, since if this is about free space, you just delete files.  

 

Older USB 2.0 caddies/adapters often don't support GPT drives, so check that first.  If yours doesn't, then the only option is to get a new USB 3 one that does.

Message 2 of 10
amtrakuk1
Aspirant

Re: Reusing RAID 1 disk to backup

Hi and thanks for the quick reply.   I guess I didnt make myself clear...   I want to bascially "zap" (very technicial term) the drive so it is reporting 3TB all the disk space.

 

The mystery is why a 3TB drive only reports 1 partition of 800 GB unused space.   How can I access the "hidden" c2.8 TB used space?

 

GPARTED only reports a single parition on /dev/sdb of 800 GB unused space.

 

Just thinking on the fly, would a better option be fitting into a machine and running a disk wiping tool or installing an OS, will that make the full 3TB available?

 

 

Message 3 of 10
StephenB
Guru

Re: Reusing RAID 1 disk to backup


@amtrakuk1 wrote:

The mystery is why a 3TB drive only reports 1 partition of 800 GB unused space.   How can I access the "hidden" c2.8 TB used space?

 

 


I think that's because your SATA->USB adapter is limited to a max size of 2 TB drives.  If I am right, you need a different adapter - nothing else will work.

 

Message 4 of 10
amtrakuk1
Aspirant

Re: Reusing RAID 1 disk to backup

I wou;dn't be suprised about the 2TB limit, I've just never come across it before - but saying that I have never delt with over 2TB before.   The caddy I'm using is a single dock version of - startech.com/HDD/Docking/dual-sata-hdd-dock~SDOCK2U33.

 

I think I leaves only one option of putting it into a desktop and see if that sees the hidden partitions 😉

Message 5 of 10
StephenB
Guru

Re: Reusing RAID 1 disk to backup

That's SATA-III, USB 3.0.  That should support GPT.

 

Message 6 of 10
amtrakuk1
Aspirant

Re: Reusing RAID 1 disk to backup

It maybe a more modern version of the one I have (about 5 years old).   I'll pop it into another machine tomorrow and see if a Linux server disk can pickup the extra hidden partitions.

Message 7 of 10
amtrakuk1
Aspirant

Re: Reusing RAID 1 disk to backup

Your spot on!   Directly on the SATA bus Ubuntu sees it as a full 3TB...   Exsactly as you say the HDD dock must not be complient with >2TB disks.  Many thanks

 

Not sure how to mark this as resolved.

Message 8 of 10
StephenB
Guru

Re: Reusing RAID 1 disk to backup


@amtrakuk1 wrote:
 Not sure how to mark this as resolved.

You can select a post as the solution (which I did on your behalf).

Message 9 of 10
amtrakuk1
Aspirant

Re: Reusing RAID 1 disk to backup

Many thanks

Message 10 of 10
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