RAID Recovery Presentation

R-Studio detects and treats valid software or hardware RAIDs as regular drives/volumes. But what to do if you have only drives or drive images of a faulty RAID? R-Studio can still help you to get the data back, provided that the drives necessary for the RAID to operate are working or you have the images of those drives. The number of drives needed in order to get data back depends on the RAID layout. For example, for a mirror (RAID 1) of two drives, at least one must be valid, whereas for a RAID 5 of three disks, the number of valid drives should be two.
Working with RAIDs in R-Studio is based on the concept of virtual volume sets and RAIDs. That is, you can construct the original RAID from its drives and/or drive images in R-Studio and process it as you would any other device object. Such a virtual object can be searched for files and scanned, and files found on it can be recovered in the same way that they would from normal drives/volumes.
Virtual RAIDs can be constructed using any device objects visible to R-Studio, be they hard drives, logical disks, or images.
Please note that virtual volumes and RAIDs are purely virtual objects, and R-Studio does not write anything on the devices from which such objects are created.
You can read more about working with RAID in R-Studio on-line help: Volume Sets and RAIDs.
Let's start the process of learning how to work with RAIDs in R-Studio by creating a simple RAID 5:

Creation of a Simple Virtual RAID 5
Parameters:
1. Number of disks: three
2. Objects in R-Studio: SCSI(3:0), SCSI(3:1), SCSI(3:2)
3. Block Size: 64 KB
4. Offset: 0
5. Block order: Left Asynchronous (Continuous)

1 2 PD
3 PD 4
PD 5 6

Where PD stands for parity of data

RAID_Recovery_Presentation_SimpleRAID5-1.png
Click image to enlarge
To create such a RAID, we
1. Click the Create virtual volume sets or RAIDs button and select Create Virtual Block RAID. The newly created virtual RAID5 object will appear on the Drive pane, and the Parents tab will appear on the R-Studio Main panel.
Check that Apply changes immediately is selected.

RAID_Recovery_Presentation_SimpleRAID5-2.png
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2. Drag the objects from which we want to create the RAID5 to the Parents tab and place them in the correct order, that is, SCSI(3:0), SCSI(3:1), SCSI(3:2).

3. Specify the correct blocks order and offset (in sectors). As soon as R-Studio detects a valid file system, a new Partition 1 object will appear on the Drive pane.

We may process this partition as a real object.

Let's enumerate the files on that partition. Just double-click the object and see the folder/file structure on the virtual RAID 5.

RAID_Recovery_Presentation_SimpleRAID5-3.png
Click image to enlarge
We can check that we constructed the RAID5 correctly. Just double-click a graphic file, and R-Studio will show its preview.
RAID_Recovery_Presentation_SimpleRAID5-4.png
Click image to enlarge
Please note that you have to specify each RAID parameter correctly - be it the device order, offset, block order, and size - to recover files successfully. R-Studio sometimes might detect an object with a valid file system even if one of the parameters is not correct, so it is a good idea to preview a file-the larger the better-to verify that you have constructed the RAID correctly. Use this formula to determine the minimum recommended size:

Block size * (number of disks -1)

For our case that minimum file size would be 64KB (the block size) three disks minus one disk (2), which comes to 128KB.

You may read about how to find RAID parameters in our articles: automatically: Automatic RAID Parameter Detection or manually: Finding RAID parameters.

You may also create your own RAID configurations, save them, and then edit and reload them. If some of the objects are missing, you may substitute them with Missing Disk or Empty Space objects. See R-Studio documentation for details.

Turning Disks On-Line and Off-Line on the Fly
You may turn the objects in the virtual RAID or volume set online and off-line by selecting/clearing the On check box on the Parents tab. It may be useful, for example, if you need to see which disk is non-actual in a RAID 5.
Actually when you turn an object off-line, R-Studio substitutes it internally with a missing disk object equal to the size of the offline disk.

Now we can proceed with a more advanced example.

Creation of an Advanced Virtual RAID 5
Now we will use the drive images as the objects from which we will create the RAID5

Parameters
1. Number of disks: three
2. Objects in R-Studio: disk image files: Y:\Disk1.dsk, Y:\Disk2.dsk, Y:\Disk3.dsk
3 Block Size: 4 KB
4. Offset: 64 KB
5. Block order: Custom

PD 1 2
PD 3 4
PD 5 6
7 PD 8
9 PD 10
11 PD 12
13 14 PD
15 16 PD
17 18 PD

To create such a RAID, we
1.Click the Create virtual volume sets or RAIDs button and select Create Virtual Block RAID. The newly created Virtual Block RAID object will appear on the Drives pane, and the Parents tab will appear on the R-Studio Main panel.

RAID_Recovery_Presentation_AdvancedRAID5-1.png
Click image to enlarge
Check that Apply changes immediately is cleared, as we will be doing a lot of editing here and there is no reason to have R-Studio execute changes unless we are through.

2. Drag the objects from which we want to create the RAID 5 to the Parents tab.

RAID_Recovery_Presentation_AdvancedRAID5-2.png
Click image to enlarge
Then place them in the correct order, that is, Y:\Disk1.dsk, Y:\Disk2.dsk, Y:\Disk3.dsk.
Select RAID5 in the RAID type, and enter the block size and offset on the Parents tab. Disregard the Block order field for the time being.

3.Manually enter 9 to the Number or rows field on the Parents tab. The Block order field will change to Custom.

RAID_Recovery_Presentation_AdvancedRAID5-3.png
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Enter the block order in the table on the Parents tab.
Using the keyboard: Arrow keys to navigate, digit and P keys to enter the block order.
Using the mouse: Right-click the cell and select the number or parity from the shortcut menu. If the block table is too large, you better use the keyboard to enter the digits.
Corrections: R-Studio will indicate if some digits are not correct by marking the cell with the red color Navigate to the required cell and enter the correct value. Use the Delete key to clear a cell.
Clear the table: Right-click the table and select Clear all on the shortcut menu.

4. When we finish filling the block order table, click the Apply button on the Parents tab.
RAID_Recovery_Presentation_AdvancedRAID5-4.png
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As soon as R-Studio detects a valid file system, a new Partition 1 object will appear on the Drive pane. We may process this partition as a real object.

Let's enumerate the files on that partition. Just double-click it and see the folders/files structure on the virtual RAID 5.

RAID_Recovery_Presentation_AdvancedRAID5-5.png
Click image to enlarge
We can check that we constructed the RAID 5 correctly. Just double-click a graphic file, and R-Studio will show its preview.

RAID_Recovery_Presentation_AdvancedRAID5-6.png
Click image to enlarge

You may also create your own RAID configurations using a description file for RAID configurations. See R-Studio on-line help: Syntax of a Description File for RAID Configurations for details.

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