Question Doubt about RAID, which to choose? And how to recover HD?

[pmurad]

Good night, how are you?I was testing on my Synology DS220j with RAID 0, it's the first time I've ever dealt with RAID, everything seemed to be flowing. But when I massively transferred some test files, the Synology froze. And it was restarted, after this freeze I could no longer access more files, the NAS became slow. So I did a hard reset and the DSM didn't want to install, I took the HDs and plugged them into a computer with Windows, one of the HDs I managed to recover through AOMEI Partition, the other one is seen by Windows, is seen by AOMEI but I can't format it or delete the partitions so that I can finally restart my work.The files, as I said, were not important. I was testing, so my questions are:Is there any RAID available by Synology similar to RAID 0? I want as much space as possible.Can this HD be recovered?I've already tried:gParted.Diskpart.AOMEI Partition.Windows Disk Management.Put it in Synology to see if it would format.Nothing worked... when I use gParted, one of the partitions appears with a little key, implying that it's locked, I don't believe this HD is lost. However, I don't know what to do to recover it.Can you help me?

 

[USAFRet]

Sigh...

With a RAID 0, any fault, either physical drive issue or the RAID controller....generally means the loss of ALL data in the array.

Any RAID 0 MUST be run with a known good full backup, for when something goes wrong.
Like it appears to have done here.


RAID 0, the data is striped across both physical drives, at a very low level.
There is rarely a fix or recovery when things go wrong.

I want as much space as possible

Example...
2x 2TB drives + RAID 0 = 4TB drive space
2x 2TB drives with NO RAID 0 = 4TB drive space.

You really really need to know what is going on and what may happen, before you go down that RAID path.

 

[hotaru.hino]

To add to the above, unless you have 10Gbit Ethernet, any sort of performance oriented configuration on a NAS is wasted simply because the network speed is the slowest part of the chain. So in addition to the increased chance of data loss from failure, you're not even gaining anything from the increased performance. There's literally no reason to use RAID0.

 

[USAFRet]

In the consumer space, there is rarely, if ever, a need for a RAID array.
Either RAID 0 striped, or RAID 1 mirrored, or any of the other more esoteric array types.

 

[Misgar]

The reason why you cannot recover any data individually from either of your RAID 0 drives at home is because each files is split up into a number of equal sized "blocks", typically 64KB in size.

Any computer file bigger than 64kB is split into a sequence of blocks.
Block 1 is written to drive 1.
Block 2 is written to drive 2.
Block 3 is written to drive 1.
Block 4 is written to drive 2
and so on with consecutive blocks written to alternating drives.

In this example:
Drive 1 contains all the odd-numbered blocks 1,3,5,7,9,...
Drive 2 contains all the even-numbered blocks, 2,4,6,8,10,...

To reconstitute this file, you need to recover all the odd numbered blocks 1,3,5,7.. off disk 1, plus all the even numbered blocks 2,4,6,8... off drive 2 and interleave them to generate blocks 1,2,3,4,5,6,7,8... That in essence is how RAID 0 works.

As USAFRet says, it is often impossible to recover data from a corrupted RAID 0 array, because only half of each file, broken up into small fragments, is stored on each drive. You need both drives to be healthy to recover each file.

If you are very, very, lucky, when a RAID 0 array dies, a specialist data recover firm might be able to recover some files, at a cost typically ranging between $500 and $1,000.

The crucial thing is NOT to attempt any data recovery yourself. You'll only make things more difficult for the professionals.

RAID 0 is a complete disaster waiting to happen if you don't have any backups.

RAID 1 would be a better option, because each drive contains an identical copy of the files stored on the other drive.

Unlike RAID 0, RAID 1 data is not split into blocks and scattered across both drives.

The down side of RAID 1 is it halves the capacity of the array. so 2 x 2TB drives in RAID 1 = 2TB storage total.

In future backup your irreplaceable data multiple times in different locations and whatever you do, stop using RAID 0.

Replace both drives and configure them as Basic, JBOD or RAID 1. See Chapter 5, Page 27 in DS220J manual. Basic and JBOD should retain all available drive space, but with zero redundancy. That's what backups are for.

 

[USAFRet]

Further, even a RAID 1 is less than optimal.

It is for physical drive redundancy, not data redundancy.

The OS and the user sees but one 'copy' of a file.
Accidental deletion, and it is gone. There is no 'second copy'.

RAID 1 is good for if you are running a webstore, and downtime == lost sales.
It allows the system to limp along until such time as you can take it off line to replace the dead drive, and allow the array to rebuild.

It does nothing really for data protection.
This is what backups are for.