- failure of one or several RAID 0 member disks;
- failure not associated with the member disks.
RAID 0 member disk failure
Since RAID 0 arrays are non-redundant, then if one of the member disks fails, then data that was on the failed disk is lost forever. Having data from the rest of the member disks you can try to recover files. However, only the files which are smaller than (N-1)*(block size) can be recovered. Even files smaller than that limit can be unrecoverable if the part of the file happens to be on a failed disk.
So in general, if one of the member disks fails beyond repair, it is impossible to recover data from RAID 0.
RAID 0 failures not associated with the loss of the member disks
Such RAID 0 failures include operator errors, controller failures, or RAID 0 controlling software failures. In this case RAID 0 configuration metadata is lost, but the member disks are working properly.
With these failures, it is possible to recover data from RAID 0. First, you should determine the array configuration. RAID 0 configuration includes:
- number of member disks,
- disk order, along with what disk was the first in the array,
- block size,
- start offset on the disks.
RAID 0 recovery with software
If the manual option seems too complex and time-consuming, or you are not that fluent with a disk editor, try the automated RAID recovery software.
- Download and launch ReclaiMe Free RAID Recovery tool.
- If it is needed, open or create disk image files of the RAID 0 member disks using the Disks button.
- Select all the member disks and click Start RAID 0. You should select at least two disks.
- The RAID 0 recovery finishes when either Scan or Confidence progress is completely filled.
- When the RAID 0 configuration parameters are detected, you should select one of the following:
- Run ReclaiMe to recover data. If ReclaiMe data recovery software has been already installed on the computer, then it is launched in RAID recovery mode and displays the partitions on the array. If you do not have ReclaiMe, you will be offered to download ReclaiMe data recovery software.
- Save layout to the XML file. Save the recovered array parameters to the file in XML format. Note that you can open this file in ReclaiMe and start to recover data off the array using ReclaiMe RAID recovery mode.
- Use with other data recovery software. Provides step-by-step instructions on how to transfer the recovered parameters to certain well-known data recovery tools. Note that the instructions are created for each particular case of RAID and you should follow them exactly. Should the need arise, the instructions can be copied to the clipboard using Copy to the clipboard button.
The same process can be applied to a RAID10 array, in which case the software detects and handles the extra mirrored copies automatically.
Manual RAID 0 recovery
How to determine the disk order
You can determine the disk order manually relying on the long text files, preferably log-files with timestamps. For searching the disk members for such files use any disk viewer tool, like WinHex. When a fragment of a suitable file would be found on one of the member disks it is needed to track what disk contains the next fragment and etc. This way, you can determine the disk order although it is impossible to find out what disk was the first.
How to determine the first disk
It is not difficult to determine what disk was the first in RAID 0. Once again, you need to use a disk viewer tool and search the member disks for:
- MBR in case of a hardware RAID - the disk that contains the MBR is the first RAID 0 disk.
- boot sector for a software RAID 0 - the disk that contains the boot sector at the beginning is the first disk.
How to determine block size (stripe size)
For a hardware RAID 0, you can determine block size by going over the possible values or look up what block size can be used in your RAID 0 implementation in the appropriate manual.
For a software RAID 0, use the standard value. For example, Windows uses a 128 sectors block for RAID 0.
How to determine start offset on the member disks
On a hardware RAID, data most likely starts at the start of the hard drive. This is equivalent to the offset of 0 (zero).
If a software RAID is used, the offsets are in most cases identical for all member disks. The offset to the start of the volume can be identified by locating the volume boot sector.
raid 0 data recovery mac, raid 0 data recovery software, raid 0 data recovery software free
Source: http://docphy.com/technology/computers/software/raid-0-recovery-2.html
No comments:
Post a Comment