DiskPatch manual - repairs on dynamic disks

Repairs on Dynamic disks

A list of terms used in this page and their explanation can be found here.

DiskPatch supports recovery of volumes on Dynamic Disks, but there are some limitations:

Only simple volumes that do not span multiple disks and/or 'segments' can be recovered.
Disks that were upgraded from a Basic disk to a Dynamic disk can be recovered by recreating a complete basic partition table layout (the disk will become a Basic disk again).
On disks that were Dynamic from the start, 4 volumes (the maximum number of allowed primary partitions) can be recovered as basic primary partitions. If more than 4 volumes were present and need to be recovered, you must follow these steps:
- recover the first 4 as primary partitions
- copy the data from these partitions to a safe place
- recover the next 4 partitions
- copy the data to a safe place
- repeat if necessary
DiskPatch can also automatically make corrections to the 'legacy' partition table if an intact LDM is present, in case the legacy partition table entry for the Dynamic Disk (a type 42h) was deleted or corrupted.

attention: After having scanned a disk, DiskPatch will always notify you if components of dynamic disks were found. So even if the disk you're repairing is not currently dynamic but was dynamic at some point in the past, DiskPatch may find traces of that dynamic disk and warn you. It's up to you to determine if these warnings are valid or not: DiskPatch has no way to determine whether the dynamic disk traces are current or not (after all you're repairing a disk so the situation on the disk is not a clean representation of how it should be; no assumptions can be made).

Repairing dynamic disks.

There are two main components in dynamic disk setups: the partition table entry and the LDM database. If one of these is gone or corrupted the dynamic disk will not be accessible.
The following situations are possible:

	1. both components exist
	2. only the partition table entry is missing
	3. only the LDM database is missing or damaged
	4. both are missing

We will now explain how to use DiskPatch to deal with each of these scenarios.

1. Both components exist:

If both components are found on the disk and you still have problems accessing the volumes, the damage is somewhere else: it's possible that the LDM itself has been damaged, or maybe parts of the volumes are damaged.
After DiskPatch has scanned the disk the following message will be displayed:

If you continue the repair the dynamic disk components that are on the disk will be ignored and a list of partitions that were found is displayed. From there on the repair is the same as the partition table repair. Please note that if you choose to repair partitions in this scenario the disk will become a basic disk. Once this step has been completed you can analyze the partitions further (if needed) and perform other repairs (if needed, like the boot sector repair). If the volumes are damaged in such a way that DiskPatch can't perform a repair you now have a good starting position to run iRecover.

2. Only the partition table entry is missing:

After DiskPatch has scanned the disk the following message will be displayed:

If you select "yes" DiskPatch will re-create the partition table entry for the dynamic disk. When completed the repair will end, you should now check if the volumes on the dynamic disk can be accessed. If not, you can try answering "no" (you will have to re-scan the disk) and try to recover the volumes individually.
If you select "no" the dynamic disk components that are on the disk will be ignored and a list of partitions that were found is displayed. From there on the repair is the same as the partition table repair. Please note that if you choose to repair partitions in this scenario the disk will become a basic disk. Once this step has been completed you can analyze the partitions further (if needed) and perform other repairs (if needed, like the boot sector repair). If the volumes are damaged in such a way that DiskPatch can't perform a repair you now have a good starting position to run iRecover.

3. only the LDM database is missing or damaged:

After DiskPatch has scanned the disk the following message will be displayed:

Please note: it is not possible to rebuild the LDM database. The only recovery option in this scenario is to continue the repair and recover the volumes individually.
If you select "yes" the dynamic disk components that are on the disk will be ignored and a list of partitions that were found is displayed. From there on the repair is the same as the partition table repair. Please note that if you choose to repair partitions in this scenario the disk will become a basic disk. Once this step has been completed you can analyze the partitions further (if needed) and perform other repairs (if needed, like the boot sector repair). If the volumes are damaged in such a way that DiskPatch can't perform a repair you now have a good starting position to run iRecover.
If you select "no" the repair will be aborted.

4. both are missing:

In this scenario no message will be displayed after DiskPatch has finished scanning the disk: if no dynamic disk components are found there is no way to tell that the disk ever was dynamic in the first place. So in this case a normal partition table repair will be performed.

Please note that for all dynamic disk repairs (with the exception of scenario 2 where you re-create the dynamic disk partition table entry) the resulting disk will be Basic. It is possible to convert the resulting basic disk back to a dynamic disk, but you should make sure the volumes are okay before doing this. Also, creating a backup would be a good idea at this point.