Within Data Protection Manager you can use custom volumes instead of the storage pool. This can be helpful in specific scenarios where the storage pool is just not the thing you need. You have to use local disks on the DPM server for custom volumes. These can be:
- Local installed (RAID) disks
- SAN storage connected by iSCSI or Fibre Channel presented as local disks
- Any other way which will show the storage as a local disk
DPM requires you to use local disks for custom volumes. Why do I not want to use my storage pool, you may think? Well, because you might want to backup specific data to specific disks for recovery. In my case, the specific LUN for the custom volumes is replicated in case of a disaster recovery. The LUN will contain specific data which then can be restored from the external replica. If you are using the storage pool, data is scattered across the pool of disks you have assigned, so you will knot know on which disks the specific data will reside. You can of course replicate the whole storage pool, but this can be very costly, especially for SAN storage.
Steps to use custom volumes
First you have to create partitions for the Replica Volume and Recovery Point Volume. Here is an example of a 100 GB disk split up in two partitions, one for the Replica Volume and one for the Recovery Point Volume:
Then you can assign the Custom Volume while creating a new protection group at the step Review disk allocation. The partitions you created will now be used for protection.
The following limitations apply:
- You cannot assign a custom volume for existing protection groups. They will have to be created again.
- The option ‘Automatically grow the volumes’ will not work.
- Custom volumes cannot be used for SQL protection.
And be aware of the following:
- If you want to reuse a partition which was used for custom volumes, do not forget to format it.
- Make sure you monitor these partitions for free disk space percentage. They will have to be extended manually when the protected source data grows and fills up the disk.
- Only use custom volumes in specific scenario’s. The recommendation is to use the storage pool whenever possible.