Case III - a totally damaged Storage Spaces database

This case deals with complete loss of Storage Spaces metadata when you:

  • deleted pools,
  • deleted spaces,
  • formatted spaces, but now want to unformat it,
  • deleted large amount of data (more than 256 MB) from a space.

In this case maps defining where data is located on physical drives are completely lost and therefore Storage Spaces doesn't show the needed pools and/or spaces. To access data you need to execute the Deep scan procedure of ReclaiMe Storage Spaces Recovery software (download).

The Deep scan procedure tries to match each slab of physical drives to a particular space on the pool. Like Find drives, the Deep scan procedure works only with those drives that you selected on the first screen before clicking the Start button. Note that you need to specify a folder to place intermediate data to. This folder must be empty and there must be free disk space of 5 GB per drive.

Performance considerations

The overall speed depends greatly on CPU power and, to a lesser extent, on the internal structure of the pool (number of spaces, slabs allocation and etc.).

In any case, it is required to read and analyze data from all the drives in the pool. At average read speed of approximately 60 MB/s it takes ten hours or so just to read data from a 2 TB drive. Analysis time depends on the following:

  • how many drives are in the original pool;
  • the total size of the drives in the pool;
  • how many signals for the analysis are found on the drives.

The estimated time of scanning and analysis depends on the density of data as well. Some data requires more complex processing and therefore more time to complete the analysis. If ReclaiMe Storage Spaces Recovery runs into area with a high data density, the estimated time may increase - this is normal. Read more on Storage Spaces recovery time.

Space content considerations

The quality of recovery depends greatly on the type of the data stored on the drives and also on the filesystems used on the pool spaces. Generally, ReFS-formatted space is better than NTFS-formatted one in terms of recovery.

If the quality of recovery is unacceptable, contact us and we will investigate the case.

Multiple spaces in a single pool

Typically, the more spaces in the pool, the more difficult the recovery task.

Note that Deep scan applied to the mirrored spaces brings several separate simple spaces - two for a regular mirror and three for a three-way mirror.

Deep scan output

When Deep scan is complete you will see spaces which ReclaiMe Storage Spaces Recovery was able to recover. Each space is characterized by the following:

  • Layout - can be either simple or parity. If your pool contained a mirror space (or three-way mirror), look for its identical parts among simple spaces.
  • Contains starting slabs - if a space contains first slabs, it is a good sign that an entire space has decent quality. First slabs store information about various important characteristics of space such as what partitions this space contained.
  • Logical size - correlates with the latest slab which the tool was able to recover for this space. In case of thinly provisioned spaces, the logical size should be close to the advertised size.
  • Allocated size - total size of all slabs reconstructed for a given space. Generally, it shows what maximum data capacity can be extracted from the space.

Typically, logical size of a space is larger than its allocated size meaning that either it is a thinly provisioned space or part of the slabs has not been identified.

You can sort the spaces according to any of the above parameters by clicking the appropriate column header.

Saving and loading Deep scan progress

To load the saved-sate files you need to click a downward arrow next to the Deep scan button and specify the folder with the saved-state files. Note that loading takes up to several minutes for an average size pool.

Once the saved-state files are loaded, ReclaiMe Storage Spaces Recovery starts to analyze the loaded data which means that you will see the progress bars indication again but this time the overall speed will be much faster. Certain data still has to be reprocessed even when the saved-state files are used. This causes a noticeable delay between Scan 1 and Scan 2 during load.

Note that even if you are going to recover Storage Spaces using the saved-state files, you still need to specify an empty folder to store the saved-state files from the current run. The saved-state files are being saved on an ongoing basis and it is not possible to turn creation of these files off. This is by design.

Downloads


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Information


Storage Spaces recovery costs Recovery cost in hardware and time

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