Custom Volumes are good when you’d like to offload a backup of something to a specific place rather than using the disk pools. My example was that the current backup location was on the same filer as my source data. I wanted to offload this single application’s backups to a separate SAN than the source data in order to have the ability to recovery from a hardware failure. There may be reasons to use this for Exchange, but I would avoid as disk pools are more seamless. The planning for a deployment of Exchange should account for this. My example is backing up archives.
The prerequisites are that you have available storage, the DPM agent installed on the target, and the needed VSS hotfix on the target.
1. Create storage
a. Carve out a volume/lun (or use DAS)
b. Attach that storage to the machine via iSCSI, a VHD hard drive if virtual, or whatever other means.
2. Figure out how much space you need for your volumes.
a. You can follow the MS guidelines using the calculator:
b. OR you can just use DPM to pull what you’ll need. This only applies to backing up current data, with however many recovery points you need. You will want to tack some extra on for growth.
i. Create a new protection group.
ii. Choose the data you want to protect
iii. Choose your retention
iv. Click modify
v. These are the values for today, so leave some overhead.
3. Carve out your two volumes; one for replica, one for recovery point.
a. Right click the unallocated space, and choose New volume..
b. Choose Simple (other options may not be grayed out)
c. Choose the Size – I had 200gb to play with, so I allocated 160 to replica and 40 to recovery point.
d. Rinse repeat for the other. This does not have to be on the same disk.
4. Create the Custom Volume and Protection Group
a. Go back to DPM and create the Protection Group as we outlined before.
b. Pull down the menu for storage, and choose custom volume
c. Assign the replica volume and recovery point volume to their respective places. Leave it at no formatting.
d. Choose manually as it is your only option.
e. Click create group (ignore the values in the box..)
f. Once this is all done, you must just manually create the new replica (Perform consistency check), and you’re set!
In order to expand storage with this configuration, you cannot use DPM, but rather you must use standard windows disk management. I realize there are no screenshots, but it was a disaster with the formatting on this blogger. I will make them available upon request.