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How to use TestDisk to recover lost partition
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schaudhary77
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Need help recovering dynamic disks

#1 Post by schaudhary77 » 30 Nov 2015, 17:26

We had 2 SAN disks attached to a Windows Server 2008 server.

Disk 1 - 300 GB
Disk 2 - 600 GB

They were configured as Dynamic. Due to an issue with the SAN, the drives got corrupted. They were coming up on Windows as "Not Initialized".

Microsoft tried several things to fix these but they were not able to.

Disk 1 - 300 GB:
Initially when I ran testdisk on the 300 GB disk, it did not show me any partitions. I changed the cylinders in the disk such that testdisk saw the size of the 300 GB disk as 900 GB. This time testdisk was able to see the partition and the files. I copied the files to a new location, issued the write command and rebooted the server. Now the drive shows up as RAW in disk management and Windows asks me to format it. Seems like the disk has been converted to a basic disk.

Disk 2 - 600 GB:
I have not been able to find any partitions or files on this disk. I have tried adjusting the cylinders such that testdisk sees the disk as 300GB, 600 GB and 900 GB. No luck.

The disks do not necessarily need to be recovered as long as I can recover all the data off of the 600 GB disk as well. Would appreciate any ideas on how to proceed.

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Fiona
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Re: Need help recovering dynamic disks

#2 Post by Fiona » 01 Dec 2015, 08:38

Can you recreate your dynamical volume exactly like before?
It would give you the possibility to run a boot sector diagnose.
Please don't reformat your volume, it'd override your underlying file system and only your freshly created file system would appear.
Then you'd need datarecovery software.
Info will follow.

Fiona

schaudhary77
Posts: 11
Joined: 30 Nov 2015, 17:06

Re: Need help recovering dynamic disks

#3 Post by schaudhary77 » 01 Dec 2015, 17:28

Hi Fiona,

Thank you for the reply.

When you say "Re-create the dynamic volume exactly like before", can you please elaborate what exactly you mean?

I had the SAN administrator create a block copy of the disks and presented to the server. They showed up as "Basic" and "Un-allocated". I converted them to "Dynamic" but they still show "Un-allocated".

300 GB:
When the drive was basic, I ran TestDisk and it detected the partition table type as "EFI GPT" and it detected the LDM database and data even before the Quick Search.

Partition Start End Size in sectors
1 P MS LDM MetaData 34 2081 2048 [LDM metadata partition]
No FAT, NTFS, ext2, JFS, Reiser, cramfs or XFS marker
2 P MS Reserved 2082 262177 260096 [Microsoft reserved partition]
2 P MS Reserved 2082 262177 260096 [Microsoft reserved partition]
3 P MS LDM Data 262178 629145566 628883389 [LDM data partition]

After converting to Dynamic, it detects the Partition Table as "Intel" and partitions below before the Quick Search.

Current partition structure:
Partition Start End Size in sectors
1 P W2K Dynamic/SFS 0 1 1 39162 95 37 629143489
No partition is bootable

600 GB:
When the disk was basic, it did not detect a partition table type on its own.
After converting to Dynamic, it detects "Intel" and the below partition (same as the 300 GB).

Current partition structure:
Partition Start End Size in sectors
1 P W2K Dynamic/SFS 0 1 1 78324 223 43 1258289089
No partition is bootable

Saurabh

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Fiona
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Location: Ludwigsburg/Stuttgart - Germany

Re: Need help recovering dynamic disks

#4 Post by Fiona » 01 Dec 2015, 18:55

When you say "Re-create the dynamic volume exactly like before", can you please elaborate what exactly you mean?
I meant, can you use your disk management console or diskpart to recreate your partitions exactly like before?
TestDisk cannot write a dynamically partition and it's not supported.
But TestDisk can convert a disk back to basic and repair the boot sector.
It would be only important when you've had spanned volume over both disks or RAID!
When you've had 2 single disk only, I'd suggest to recover your partitions as basic disks, because TestDisk can search for partitions and you could write them into your partition table.
Afterwards, if you'd like to, you can convert them to dynamically disks.

The question is, did you use two single disks or a spanned or RAID volume?

Info for a diagnose will follow.

Fiona

schaudhary77
Posts: 11
Joined: 30 Nov 2015, 17:06

Re: Need help recovering dynamic disks

#5 Post by schaudhary77 » 01 Dec 2015, 19:07

It is a spanned volume. The 300 GB disk was setup first and then the 600 GB was added to expand the volume.

The main thing I need to do right now is extract the data from the 600 GB disk, whichever way possible. I already have the data from the 300 GB disk.

Saurabh

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Fiona
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Location: Ludwigsburg/Stuttgart - Germany

Re: Need help recovering dynamic disks

#6 Post by Fiona » 01 Dec 2015, 19:48

I have tried adjusting the cylinders such that testdisk sees the disk as 300GB, 600 GB and 900 GB. No luck.
Please don't adjust any cylinder using the testdisk menu geometry nor anything else!
You'd need both disks to recover any data off of your 600 GB disk.
Because your partition and file system were spanned over 2 disks and running a diagnose on 1 disk only doesn't help!
When you used the complete space of both disks, you could recreate a dynamically partition.
You should only create your dynamically partition (it's like a trick, you're using your diskmanagement console to create a partition and TestDisks job will be to run a boot sector diagnose on your created partition).
Either TestDisk displays the backup of your boot sector or you can run a RebuildBS (rebuild boot sector) on your created partition.
When TestDisk finds your underlying file system and is able to repair or rebuild your boot sector it would make your data available again.

Did you use the whole space before?

If yes, create your partition (your disks must be dynamically).
Note: Partitions don't start within a partition nor it hasn't any affect to your file system.
Partitions are written either in your partition table (like Intel MBR or GUID partition table) or dynamically disks puts the info at the end of your disk.
Partitions starting by its boot sector after the MBR or GPT.
So it doesn´t touch any data.

After partition creation, windows asks you to format your partition.
Don't format your partition!
Formatting a partition can override your underlying file system and you'll need datarecovery software.

Using TestDisk to run a boot sector diagnose:
Start TestDisk, under Disk selection, you have to select your created spanned Drive and not any disk.
Partition table type is "None", because you run TestDisk on a Drive or better to say on your created dynamically partition!
Don't run TestDisk Analyse but Advanced / Boot.
Please upload a snapshot.
When your boot sector and its Backup are BAD, run RebuildBS.
When your backup of the bootsector is Ok or RebuildBS was successful, you'll see the menu "List".
Have a try to list your files.

Please let me lnow!

Fiona

schaudhary77
Posts: 11
Joined: 30 Nov 2015, 17:06

Re: Need help recovering dynamic disks

#7 Post by schaudhary77 » 01 Dec 2015, 20:05

Don't run TestDisk Analyse but Advanced / Boot.
There is no option for Boot under Advanced. Please see below.


TestDisk 7.0, Data Recovery Utility, April 2015
Christophe GRENIER <grenier@cgsecurity.org>
http://www.cgsecurity.org

Drive Z: - 966 GB / 899 GiB - CHS 117486 255 63

Partition Start End Size in sectors
> P Unknown 0 0 1 117486 189 15 1887424512



>[ Type ] [Image Creation] [ Quit ]
Change type, this setting will not be saved on disk

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Fiona
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Location: Ludwigsburg/Stuttgart - Germany

Re: Need help recovering dynamic disks

#8 Post by Fiona » 01 Dec 2015, 21:03

Your partition type is Unknown.
You can use Type to add your partition type.
If you'd get asked for the partition code, 07 is NTFS and 0c for FAT32.
Exfat is not supported.
After adding your partition type, Boot will be available.
300 GB and 600 GB is 900 GB but your drive displays a size of 966 GB?
Is this correct?

Fiona

schaudhary77
Posts: 11
Joined: 30 Nov 2015, 17:06

Re: Need help recovering dynamic disks

#9 Post by schaudhary77 » 01 Dec 2015, 21:47

Yes, the size of 966 GB is correct.

I have requested a copy of the original disks from the SAN administrator (had made some changes to the last one which I wasn't comfortable with). That takes a couple of hours. Will upload a snapshot of advanced -> boot once it is available.

Saurabh

schaudhary77
Posts: 11
Joined: 30 Nov 2015, 17:06

Re: Need help recovering dynamic disks

#10 Post by schaudhary77 » 02 Dec 2015, 02:40

Question - The disks are marked as "Basic". Should I convert them to "Dynamic" first and then create the spanned volume?

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