On the technet DPM team blog Prashant Kumar (Program Manager | DPM Team) wrote a post with a lot of interesting background information on DPM 2010.
He describes how some of the new features in DPM 2010 help you to meet you business SLA’s.
Post can be found here
Quote from http://blogs.technet.com
A potential problem with Volume Manager on Windows Server 2008 systems may lead to data loss.
This hot fix is not DPM-specific. However, because DPM servers do utilize dynamic disks, it is important to apply this hotfix on WS08-based DPM servers so that your backup-data is not lost from the DPM storage pool.
For more information please read the link below to the hot fix.
962975 Dynamic disks are marked as "Invalid" on a computer that is running Windows Server 2008 or Windows Vista when you bring the disks online, take the disks offline, or restart the computer if Data Protection Manager is installed
http://support.microsoft.com/kb/962975
This hot fix does not apply to Windows Server 2008 R2
As you might have noticed there is no documentation on DPM 2010 included in the RC download.
Mike of Scug.be has done a good job in making screen-shots of the upgrade from DPM 2010 beta to DPM 2010 RC.
This might saves you from some headaches.
http://scug.be/blogs/scdpm/archive/2010/02/10/dpm-2010-upgrade-from-beta-to-rc.aspx
There are many reasons why a SharePoint recovery point keeps failing. It also a good idea to check the logs on the Web front-end and SQL backend server.
In our case we found the following errors in the system log of the SharePoint Web front-end 
| Event Type: Error |
| Event Type: Error |
Reason / Cause
In our case this error was caused by a Password change of the account we used (a long time ago) to configure SharePoint protection.
Solution
After you change the password of the account you used for the ConfigureSharePointProtection, you need to run the commands again on the SharePoint Web Front-end machines.
ConfigureSharePoint –EnableSharePointProtection
ConfigureSharePoint –EnableSPSearchProtection
All available commands: http://technet.microsoft.com/en-us/library/dd441708.aspx
When you try to add a SharePoint farm to a DPM protection group you may get the error below.
| The operation failed because an error occurred while enumerating the data source for Virtual SSP Writer. Check to see that the data source specified in the error message is online and accessible. ID: 921 Details: The system cannot find the path specified (0x8007003) |
You will receive this error when trying to expand the SharePoint Front-end server.
Resolution \ Cause:
The might be caused by a missing MTATempStore$ share on your SharePoint frontend server. Check if the directory %program files\Data Protection Manager\Temp is shared as MTATempStore$. The default permission is Everyone full control. This can be changed as long as the account you used for configuring the WssCmdletsWrapper has access to the Share.
Now you can retry to add the SharePoint farm to the Protection group
Storage is the most essential part of the hardware for Data protection Manager. In most cases you will use disk for your short term protection.
But how many disk space to you need?
To answer this question Microsoft has developed three Excel calculation sheets (still in draft) for: Exchange, SharePoint and Hyper-V
Example 1: Hyper-V Calculation
Example 2: Exchange Protection
Example 3: SharePoint protection
As you can see in the examples above, the sheets calculate more then only the required disk space. It also calculate the number of DPM servers required, hardware for DPM server needed. Configuration of the DPM server; like page file and Database size. You will also find an estimated backup and recovery time for your protected servers.
The sheets are available at the Microsoft download site: http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=c136c66c-bd4a-4fb1-8088-f610cd02dc51
The RC version of DPM 2010 is now available for download – Lets get started