RAID-0 format

  • Thread starter Thread starter MicroX
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MicroX

Does anyone know where I can get a detailed description of how a RAID
drive is built at a low-level? I mean what is the actual physical
distribution of the sectors across the disks, and if there are any
special sectors added for RAID-specific information actually on the
disk. All I could find by Googling is general conceptual descriptions
of how RAID works. I am interested specifically in RAID-0 (striping).

I am thinking to maybe write a script to build a single disk back out
of a RAID array. I know there are already "destriping" tools out there,
but the ones I tried failed to recover a corrupted disk, so I wanted to
inspect it manually.

Thanks!
 
Previously MicroX said:
Does anyone know where I can get a detailed description of how a RAID
drive is built at a low-level? I mean what is the actual physical
distribution of the sectors across the disks, and if there are any
special sectors added for RAID-specific information actually on the
disk. All I could find by Googling is general conceptual descriptions
of how RAID works. I am interested specifically in RAID-0 (striping).
Click to expand...

The RAID it self is just striping with the block size configured.
Nothing to it at all. The RAID superblock is not standardized in
size, placement or contents. Every implementor is doing his/her
wn thing ...
I am thinking to maybe write a script to build a single disk back out
of a RAID array. I know there are already "destriping" tools out there,
but the ones I tried failed to recover a corrupted disk, so I wanted to
inspect it manually.
Click to expand...

Best approach is to use the controller with two empty disks and
see what it is putting onto them and where.

Arno
 
MicroX said:
Does anyone know where I can get a detailed description of how a RAID
drive is built at a low-level? I mean what is the actual physical
distribution of the sectors across the disks, and if there are any
special sectors added for RAID-specific information actually on the
disk. All I could find by Googling is general conceptual descriptions
of how RAID works. I am interested specifically in RAID-0 (striping).

I am thinking to maybe write a script to build a single disk back out
of a RAID array. I know there are already "destriping" tools out there,
but the ones I tried failed to recover a corrupted disk, so I wanted to
inspect it manually.
Click to expand...

The answer is there is no standard format for any RAID implementation.
The general implementation is the only thing that is written down, but
the details are left upto the individual companies. It's the exact same
thing whether we're talking about software or hardware RAID -- no
standard implementation between each other.

All RAID implementations maintain a private data section that keeps
track of the relationships between the bunch of disks. The private data
is usually distributed over all of the disks, or at least a significant
portion of those disks, for redundancy. The private data is variously
known as metadata, private data, raid data, etc. These terms are usually
created by the companies' own marketing departments.

Yousuf Khan
 
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