Intro to DPM 2007-SP1

In the coming weeks, we will be discussing the new features of DPM 2007 SP1 to enough depth that you can implement them into a new or existing environment. We will also be covering some of the basics on how to install and configure, at a very basic level, the applications that DPM will be protecting.

This information is targeted towards DPM administrators who have little-to-no experience with the technologies that DPM SP1 provides support for such as SQL Database Mirroring, Exchange SCR, Hyper-V, and SharePoint Search index servers.

Here is a summary list of those new features:

• Mirrored Database protection for SQL 2005 and SQL 2008 databases
• Mirrored Content and Search Index Database protection for SharePoint WSS and MOSS farms
• Search Index database protection and recovery for SharePoint farms
• Distinct Content Database checking
• Exchange 2007 SCR protection
• Hyper-V guest OS protection
• Cross-Forest Protection
• Additional support provided for Local Data Sources which include locally installed Hyper-V guests

Let’s take a look at these features at an introductory level; future blogs will go in depth on how to configure, protect, and recover these new data sources.

Mirrored SQL Database Protection

Database mirroring is a feature introduced with SQL Server 2005 SP1 which allows transactions to be passed to a secondary server (mirror) shortening the failover time needed to bring the alternate database online for user access.

DPM provides support based on the configurations that the SQL Server support teams support. As an example, DPM can protect a mirrored database after failover and without manual intervention. DPM can also protect a mirrored database that spans multiple domains or where one of the partners in the mirror is on a Windows Failover cluster.

The blog on SQL Database mirroring will go into the details of setting up and mirroring a given database and what steps are needed to protect and recover the data. We will also discuss the mechanisms in DPM 2007 SP1 that allow for continued protection after a failover of a mirrored database, whether the failover is manually or automatically instigated.

DPM does not extend limitations of a protected product but is designed to fit within that product’s support scenarios. For example: it is a limitation of SQL that mirroring must be removed in order for any data to be restored. DPM does not work around this limitation, but works within it.

For the full set of features DPM offers with regard to SQL Server database mirroring, please refer to the blog on SQL Database mirroring. The examples provided in the blog cover the protection of a mirrored database where one side of the mirror resides on a Windows Failover cluster.

SharePoint Features

Mirrored Content and Search Index Database protection

As with the protection of mirrored SQL databases, as of SP1 for DPM 2007, protection is provided for any SharePoint content databases that have been mirrored in SQL Server 2005 or SQL Server 2008 along with any Search Index databases that have been mirrored in SQL.

Search Index databases protection

Prior to SP1 for DPM 2007, the failure or corruption of a search index database could result in re-crawling of the sites in a farm and this process in large implementations could run for more than 24 hours. With the release of SP1, DPM is able to restore the index database to its original location so that a subsequent crawl of the SharePoint content could be reduced from 24 hours to just 2-3 hours. This saves stress on users who actively search for content and reduces recovery down-time by allowing administrators to effectively seed the search index database and then run a crawl to update the database with any changes.

Distinct Content Database Checking

Invariably, content databases in large farms will become inconsistent from time to time. Prior to SP1 for DPM 2007, if any content database became inconsistent, the entire farm went unprotected until the consistency checks for every database completed. Forcing healthy data sources into an unprotected state due to one or two unhealthy data sources was not ideal for large SharePoint farms.

As we will see when this feature is discussed in greater detail in a later blog, any content database that is showing as “consistent” will see its job moved immediately into the Completed Jobs list. Any remaining databases whose state is “ inconsistent” will remain until the consistency check completes on those respective databases. At that point, the consistency check job for the Farm will run and complete.

This ability becomes of paramount importance considering that the failover of a mirrored content database renders that content database inconsistent until the automated consistency check job runs to correct this issue. The time savings of being able to isolate a content database in order to run a needed consistency check, as compared to the entire list of databases in the farm, will be the greatest for the largest SharePoint farms.

Exchange SCR Protection

Exchange Server 2007 Service Pack 1 introduced a new replication topology called Standby Continuous Replication, or ‘SCR’ for short. In an upcoming blog on SCR protection, we will learn about SCR and what configurations are supported.

We will also discuss how to setup SCR on a mailbox database and how to protect the Source and Target servers. Protecting the Target SCR server is crucial as Exchange does not natively provide backup support for the Target server, only the Source server. To fill this gap, DPM 2007 SP1 introduces this capability.

Because Exchange SCR configuration and management is handled from within the Exchange Management Shell CLI (Command Line Interface) and not from the Exchange Management Console, the blog will cover the switches for the necessary cmdlets in detail. Familiarity with PowerShell is needed for support of this technology and extra detail is provided in the appropriate blog.

We will also cover the recovery capabilities and limitations imposed by Exchange, as there are some limitations we must work within due to the way SCR is implemented within Exchange.

Hyper-V Guest OS Protection

Virtualization technologies like Virtual Machine Manager and Hyper-Visor (Hyper-V) have become widely adopted because of the tremendous cost savings provided by each. With the release of Service Pack 1 for DPM 2007, protection of the Hyper-V guests becomes another key area of protection that must be filled.

DPM’s ability to protect Hyper-V guests covers a rich array of capabilities that include the ability to protect guests in a Hyper-V host installation based on Windows Server 2008 Core as well as the Full versions. With Integration Services, the Hyper-V VSS writer makes it possible for DPM to protect guests that are live without having to pause or save them, which would interrupt user connectivity.

One limitation is that DPM does not protect all other drives connected to the guest OS. In cases where iSCSI connections to other storage exists in the guest, the DPM agent should be installed inside of the guest partition to provide a protection solution of the additional iSCSI volumes.

For guest operating systems that do not support Integration Services like Windows NT 4.0, DPM will pause the system before a backup is taken. This means that DPM is now capable of protecting Windows NT 4.0, Windows 2000, and Linux systems that are guests of a Hyper-V host system. In these situations, DPM will only backup the local storage (VHD) files and not remote disks. Using this method, DPM is also capable of protecting dynamic disks inside of a VM and pass-through disks (physical host-machine disks mapped to a VM for use).

When the offline backup is taken, DPM requests the machine to be paused. The paused system’s VHDs are then snapshot, and the guest OS is brought back online.

DPM is able to restore the base files to any location or the full guest back to its original location. When restored to its original location, the administrator only needs to power the system on and verify the data is there. No other configuration changes are necessary within the Hyper-V Manager.

Clustered guests can also be protected by DPM as long as both host systems have the DPM agent installed so that regardless of which system the guest is online and running on, the DPM Server can contact an agent to initiate protection of the files. DPM also supports Virtual Machine Manager (VMM) Quick Migration.

Cross-Forest Protection

The ability to protect data sources on a server in a different domain within the same forest has been a feature of DPM since its initial release. With the release of SP1 for DPM 2007, protection is now being provided across a 2-way forest-to-forest trust. The only requirement for this feature is that the cross-forest trust must be 2-way.

Cross-forest trust provides a new type of Windows trust for managing the security relationship between two forests—greatly simplifying cross-forest security administration and authentication. Users can securely access resources in other forests without sacrificing the single sign-on and administrative benefits of having only one user ID and password maintained in the user's home forest. This provides the flexibility to account for the need for some divisions or areas to have their own forest, yet maintain the benefits of Active Directory.

Local Data Source Protection

To help Enterprise level customers who have single server installations in remote offices, DPM 2007 SP1 supplements the local data source protection capabilities for files, and folders available prior to SP1 by adding Hyper-V guests as well. With more Enterprise-level customers setting up remote offices with a limited number of multi-use servers, DPM is now capable of protecting data sources locally. Considering also that most remote offices are across low-bandwidth links, there may not be sufficient bandwidth to handle the amount of data DPM must transfer in order to protect it.

Summary

We discussed, at a very high level, several of the new feature offered with the release of DPM 2007 SP1. From this blog, we will move into more in-depth discussions of each feature. We will demonstrate how to implement the basic features of the applications DPM protects for DPM administrators since a cursory knowledge of each protected application is necessary for implementing and managing protection with DPM.

Vic Reavis
Support Escalation Engineer
Microsoft Enterprise Platforms Support