Question Using one HDD from a RAID 1 setup to backup the same RAID 1 files

[jojoharry16]

It's not straightforward, so I'll try and clear it up:

I have 2 large HDDs in my PC using ReFS to act like RAID 1 redundancy. I used ReFS because I honestly thought Linux could interact with it just like NTFS, but turns out I was wrong and now all my data is unreadable.

My question is, since the data should be duplicated, can I take one of the HDDs, format it to be ext2 (for example), and copy the data from the remaining ReFS HDD to the new ext2 HDD?

And if I do that, is there a way to then format the second HDD to ext2 and use it to add redundancy to the existing data?

If anything is unclear I'll do my best to clarify, any and all help is greatly appreciated

 

[USAFRet]

It's not straightforward, so I'll try and clear it up:

I have 2 large HDDs in my PC using ReFS to act like RAID 1 redundancy. I used ReFS because I honestly thought Linux could interact with it just like NTFS, but turns out I was wrong and now all my data is unreadable.

My question is, since the data should be duplicated, can I take one of the HDDs, format it to be ext2 (for example), and copy the data from the remaining ReFS HDD to the new ext2 HDD?

And if I do that, is there a way to then format the second HDD to ext2 and use it to add redundancy to the existing data?

If anything is unclear I'll do my best to clarify, any and all help is greatly appreciated

No.
If you"format" it to be ext2...how do you propose to get the data? It is gone, from that formatting action.


RAID 1, either Windows or Linux, is NOT a good backup concept.

RAID 1 is for continued uptime, not data security and redundancy.

 

[jojoharry16]

No.
If you"format" it to be ext2...how do you propose to get the data? It is gone, from that formatting action.


RAID 1, either Windows or Linux, is NOT a good backup concept.

RAID 1 is for continued uptime, not data security and redundancy.

Thanks for your input, I never mentioned backup, though. I have redundancy in my machine because I lost my data once and I don't want to go through that again because of a faulty drive. I have backups of the important stuff on an external Nextcloud server.

Since I have 2 HDDs with mirrored contents (let's call them A and B), I was wondering if formatting A to ext2 and then copying the contents of B to it is feasible, if so is it common practice; or if there's a known alternative other than buying another HDD.

 

[USAFRet]

Thanks for your input, I never mentioned backup, though. I have redundancy in my machine because I lost my data once and I don't want to go through that again because of a faulty drive. I have backups of the important stuff on an external Nextcloud server.

Since I have 2 HDDs with mirrored contents (let's call them A and B), I was wondering if formatting A to ext2 and then copying the contents of B to it is feasible, if so is it common practice; or if there's a known alternative other than buying another HDD.

In the consumer world, RAID 1 or anything similar is mostly a waste, and not needed.

Within my NAS, I have a routine to copy the contents of one volume to another, on a hands off schedule.
But that is not a 100% RAID 1 style 'mirror'.

Currently, it seems you have ONE copy of your data in that mirror. That is not optimal.
Accidentally delete something, it is gone.

Might your procedure work?
Maybe.
But I wouldn't trying it without a known good copy of everything in that array. Too many ways for things to go wrong.

 

[Misgar]

I used ReFS because I honestly thought Linux could interact with it just like NTFS,

To clarify, were you running these drives in a Linux system or a Windows system? Were you accessing files from the array over a LAN?

My question is, since the data should be duplicated, can I take one of the HDDs, format it to be ext2

I love the phrase "should be duplicated". The last thing I'd do is format either of the two disks. How do you know if the disk you've chosen to keep (by tossing a coin) is OK. It might be full of pending sectors or bad blocks. By destroying the data on the other drive, you might have reduced your chances of file recovery from poor to absolute zero.

A quick scan of this page shows the R in ReFS stands for Resilient, which doesn't seem to be the case for your array. It also mentions that ReFS protects against data corruption, so all the more reason to keep both drives intact. I've not used ReFS myself.
https://www.howtogeek.com/311840/what-is-refs-the-resilient-file-system-on-windows/

If you cannot find an expert on Tom's to guide you through some simple tests, consider forking out for a professional data recovery agency, if the files are sufficiently important. If not, put it down to experience and make sure all important files are saved to at least three separate devices or media. A RAID array, no matter how fault tolerant, counts as only one copy, not two, let alone three.

The most I'd do is a non-destructive Read test of each drive on its own, using Hard Disk Sentinel. That way you could get an idea if the drives are readable and the surfaces are intact, or covered in bad blocks.
https://www.hdsentinel.com/