How to fix lost storage pool disk on DPM 2010?

I have lost all Storage Pool Disks from DPM 2010 installation. Hence I have recreated a lank disk and added the same on storage pool. But there was no data available which I can reallocate. Another thing what I wanted talk about disk space. Previously it was using RAID5 and after replacement it has became RAID 6. So I have lost some disk space as compared to the original one. There was no issue with Disk1 but Disk 2 was having low space. Disk2 used 8155GB where empty space was 8377GB. Can you tell me about root cause of problem? any suggestions to resolve the matter will be highly appreciated. Thanks a lot in advance.

Well if you are using single disk on DPM storage pool then it would be really simple to recover quit easy as replica and recovery points are created on single disk only. However if you added couple of disk on DPM storage pool the DPM would make use of both the disk. I mean Replica would get created on one disk where as recovery would created on another one. So it would be quite easy to recover if you have lost any of disk.
As time passes you will try to modify disk allocation for this particular replica and recovery point volume supposed to grow volume. If there is need to increase volume then DPM auto-grow is enabled . so it does not mean that there will be need of growing of volume on the same physical disk. Hence volume is not missing rather it showing failed state.
In order to resolve any of above mentioned steps you have to perform below mentioned steps.

You have to replace failed physical disk and get a new disk on your DPM storage pool. If you get missing disk then you should simply leave it. after that you have to execute DPMSYNC –reallocatereplica

After completion with execution of above mentioned command all new replica as well as recovery point volumes are getting recreated on disks which you are having on storage pool.
But still you might get failed state in Windows disk management or diskpat.exe for volumes whhihc you have created. Volumes are supposed had one or more extents located on your disk. DPM is not able to reconstruct those volume. Hence you will need delete failed volume by making use of disk management or diskpart.exe. After that you have to simply execute DPMSYNC –reallocatereplica on your command prompt in order to recreate those volume.

After recreation of volumes you will not be able to see missing volumes when you click on protection tab. Also you will see in green color after having Consistency check. Once all data sources are in green in color then you have to remove data sources which has been displayed into DPM storage pool. Also you have to delete missing dynamic disk from Windows disk management.

The DPMSync command can be used to enable sync DPM database. You can use the same on disks of storage pool and installed on Protection ?agent. it can be used for restoring DPM database, sync DPM database by using Replica in Storage Pool. Laos by using above command you can restore the database and reallocated all replicas which are missing. There is no need of executing DpmSync if you begin with new DPM database. You should use Dpmsync when you are running original DPMDB for ne volumes. If there are no existing volumes then you will not be able to create backup.