convert dynamc disk with corrupt filesystem

Using TestDisk to repair the filesystem
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Posts: 2
Joined: 24 Apr 2013, 04:39

convert dynamc disk with corrupt filesystem

#1 Post by philjor »

There must be an easier way than to copy all the files and then reformat.
I have a particular situation: I created a dynamic disk without really wanting to. anyway, I was able to move the disk between two distinct identical Win7 systems but now the disk was corrupted or whoknowswhat caused ti to prevent bootup. Not to worry, remove the guilty disk and boot – no problem. But now I must change the dynamic to basic. The disk has 4 sections (not partitions – slices if you will) –
1. P LDM with metadata 34 to 2081 sectors (2048) partition;
No FAT, NTFS, ext2, JFS ….. etc. etc. so no file system ???
2. P MS Reserved 2082 to 262177 (260096) ;
2. P MS reserved ; and
3. P MS LDM Data 262178 to 3907029134 (3906766957)
Note HxD shows 0 sector as practically empty; there are 2 MS Reserved partitions ? with same coordinates – the numbers are correct
This is a single partition (2TB); the data is intact but there is a lot of it and it is slow to copy by TestDisk.
Since I don’t know what to do with this, question; what do I do?
There is no 42 or 07 entry in the 0 sector – in place there are four consecutive FFs and the rest of the 0 sector is rather empty! screen capture attached ...
Could I do something like copy the first sector 0 or more from another disk, a twin to this one but not dynamic, and paste it to the sick one ? Or do I create some kind of boot sector in the space from 0 to 33 sectors?
This disk is not intended for booting ever - it is only for storage a processing image and video files.

Thanks for any help.
screen capture on win7 with sata6 disk on usb3 dock
screen capture on win7 with sata6 disk on usb3 dock
screen capture.jpg (145.49 KiB) Viewed 3011 times

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Re: convert dynamc disk with corrupt filesystem

#2 Post by Fiona »

Disks up to 2 TB can use Intel MBR.
Disks bigger than 2.2 TB require GPT.
If you'd like to convert a dynamic disk to basic means tha a basic disk is an intel mbr disk and contains partitions.
TestDisk works a lot faster on Intel MBR disks because testdisk searches each cylinder.
The size of a cylinder with 255 Heads and 63 sectors per Head, is about 8 MB.
If you use EFI GPT partitions are in slices and will scan each sector.
That's why GPT-disks take a bit longer to scan, but there is a trick, if testdisk found a partition, you can press F (upper case) to jump to the end of a partition and testdisk scans for the next partition.
Now it's important that testddisk finds your partitions and displays your data.
Then you can recover them, either to writing your partition to an Intel-partition table, or if you'd like to you can also reciver your oaertitions to GPT
But in this case your disk must be a GPT-disk.
You can watch the status of you disk in your disk management console at the left side in that small square.
Basic is an Intel MBR and GPT as it's described.
Often Windows reports disks wrong.
That's why it's recommedable to right click in the left small sqare of your disk in your disk management console and check it.


Posts: 2
Joined: 24 Apr 2013, 04:39

Re: convert dynamc disk with corrupt filesystem

#3 Post by philjor »

Thanks, Fiona for the information.
Unfortunately, I was unable to save the disk by rewriting the partition tables... I tried EFI, mbr and I don't recall what else... nothing worked ! I don't understand exactly what happened, but I suspect the problem is with the Asus motherboard that goes a bit quirky when overclocked... but then again, it really works well, at 4.7ghz from 3.4, once it is up and running... but it is also quirky with USB (at least 8 USB3 connections) disks and keys... and even the eSata is problematic... I think I'm goint to RMA it !
I was hoping it would be possible to reactivate the disk so I would not have to copy all the files I had on it... fortunately, even if it took me a while to figure things out, I was able to copy everything to another disk and then I played around with TestDisk and with HxD in copying from other disks sectors to the sick one and trying to get things accepted by Windows... as expected, nothing worked, but the exercise was worth while... I finally realized that I could have just selected all on the good partition holing the important files and just wait a few hours while they would be copied. For this, TestDisk is fantastic. I didn't lose a bit or byte and was able to format the disk and recopy all the files to it and all is well and good in Internet Wonderland... :)
Just one small comment, would it is possible to set up a way to select all (with "a" ) and then deselect unwanted files, like hyberfil and pagefile or system volume info or even $Recycle Bin... often these directories and/or files are not important to save and deselecting them can save a lot of time when making backups of the important files.
Thanks again for your help. I really do like TestDisk... !