Read more about this book

(For more resources on Microsoft, see here.)

DPM structure

In this section we will look at the DPM file structure in order to have a better understanding of where DPM stores its components. We will also look at important processes that DPM runs and what they are used for. There will be some hints and tips that you should know about that will be useful when administering DPM.

DPM file locations

It is important to know not only how DPM operates, but also to know the structure that is underneath the application. Understanding the structure of where the DPM components are will help you with administering and troubleshooting DPM if the need arises. The following are some important locations:

• The DPM database backups are stored in the following location. Also when you make backup shadow copies for the replicas these will be stored in this directory. You would make backup show copies of your replicas if you were archiving them using a third-party backup solution:
  C:Program FilesMicrosoft DPMDPMVolumesShadowCopyDatabase Backups
• The following directory is where DPM is installed:
  C:Program FilesMicrosoft DPM
• The following directory contains PowerShell scripts that come with DPM. There are many scripts that can be used for performing common DPM tasks.
  C:Program FilesMicrosoft DPMDPMbin
• The following folder contains the database and files for SQL reporting services:
  C:Program FilesMicrosoft DPMSQL
• The following directory contains the SQL DPM database. MDF and LDF files:
  C:Program FilesMicrosoft DPMDPMDPMDB
• The following directory stores shadow copy volumes that are recovery points for a data source. These essentially are the changed blocks of VSS (Volume Shadow Copy Service) (Shadow Copy).
  C:Program FilesMicrosoft DPMDPMVolumesDiffArea
• The following folder contains mounted replica volumes. Mounted replica volumes are essentially pointers for every protected data object that points to the partition in a DPM storage pool. Think of these mounted replica points as a map from DPM to the protected data on the hard drives where the actual protected data lives.
  C:Program FilesMicrosoft DPMDPMVolumesReplica

DPM processes

We are now going to explore DPM processes. The executable files for these are all located in C:Program FilesMicrosoft DPMDPMbin. You can view these processes in Windows Task Manager and they show up in Windows Services as well:

The following screenshot shows the DPM services as they appear in Windows Services:

We will look at what each of these processes are and what they do. We will also look at the processes that have an impact on the performance of your DPM server. The processes are as follows:

• DPMAMService.exe: In Windows Services this is listed as the DPM AccessManager Service. This manages access to DPM.
• DpmWriter.exe: This is a service as well, so you will see it on the services list. This service is used for archiving. It manages the backup shadow copies or replicas, backups of report databases, as well as DPM backups.
• Msdpm.exe: The DPM service is the core component of DPM. The DPM service manages all core DPM operations, including replica creation, synchronization, and recovery point creation. This service implements and manages synchronization and shadow copy creation for protected file servers.
• DPMLA.exe: This is the DPM Library Agent Service.
• DPMRA.exe: This is the DPM Replication Agent. It helps to back up and recover file and application data to DPM.
• Dpmac.exe: This is known as the DPM Agent Coordinator Service. This manages the installations, uninstallations, and upgrades of DPM protection agents on remote computers that you need to protect.

DPM processes that impact DPM performance

The Msdpm.exe, MsDpmProtectionAgent.exe, Microsoft$DPM$Acct.exe, and mmc.exe processes take a toll on DPM performance. mmc.exe is a standard Windows service. “MMC” stands for Microsoft Management Console application and is used to display various management plug-ins. Not all but a good amount of Microsoft server applications run in the MMC such as Exchange, ISA, IIS, System Center, and the Microsoft Server Manager. The DPM Administrator Console runs in an MMC as well. mmc.exe can cause high memory usage. The best way to ensure that this process does not overload your memory is to close the DPM Administrator Console when not using it.

MsDpmProtectionAgent.exe is the DPM Protection Agent service and affects both CPU and memory usage when DPM jobs and consistency checks are run. There is nothing you can do to get the usage down for this service. You just need to be aware of this and try not to schedule any other resource intensive applications such as antivirus scans at the same time as DPM jobs or consistency checks.

Mspdpm.exe is a service that runs synchronization and shadow copy creations as stated previously. Like MsDpmProtectionAgent.exe, Mspdpm.exe also affects CPU and memory usage when running synchronizations and shadow copies. Like MsDpmProtectionAgent.exe there is nothing you can do to the Mspdpm. exe service to reduce memory and CPU usage. Just make sure to keep the system clear of resource intensive applications when the Mspdpm.exe is running jobs. If you are running a local SQL instance for your DPM deployment you will notice a Microsoft$DPM$Acct.exe process. The SQL Server and SQL Agent services use a Microsoft$DPM$Acct account. This normally runs on a high level. This service reserves part of your system’s memory for cache. If the system memory goes low, the Microsoft$DPM$Acct.exe process will let go of the memory cache it has reserved.

Important DPM terms

In this section you will learn some important terms used commonly in DPM. You will need to understand these terms as you begin to administer DPM on a regular basis. You can read the full list of terms at this site:

http://technet.microsoft.com/en-us/library/bb795543.aspx

We group the terms in a way that each group relates to an area of DPM. The following are some important terms:

• Bare metal recovery: This is a restore technique that allows one to restore a complete system onto bare metal, without any requirements, to the previous hardware. This allows restoring to dissimilar hardware.
• Change journal: A feature that tracks changes to NTFS (New Technology File System) volumes, including additions, deletions, and modifications. The change journal exists on the volume as a sparse file. Sparse files are used to make disk space usage more efficient in NTFS. A sparse file allocates disk space only when it is needed. This allows files to be created even when there is insufficient space on a hard drive. These files contain zeroes instead of disk blocks.
• Consistency check: The process by which DPM checks for and corrects inconsistencies between a protected data source and its replica. A consistency check is only performed when normal mechanisms for recording changes to protected data, and for applying those changes to replicas, have been interrupted.
• Express full backup: A synchronization operation in which the protection agent transfers a snapshot of all the blocks that have changed since the previous express full backup (or initial replica creation, for the first express full backup).
• Shadow copy: A point-in-time copy of files and folders that is stored on the DPM server. Shadow copies are sometimes referred to as snapshots.
• Shadow copy client software: Client software that enables an end-user to independently recover data by retrieving a shadow copy.
• Replica: A complete copy of the protected data on a single volume, database, or storage group. Each member of a protection group is associated with a replica on the DPM server.
• Replica creation: The process by which a full copy of data sources, selected for inclusion in a protection group, is transferred to the DPM storage pool. The replica can be created over the network from data on the protected computer or from a tape backup system. Replica creation is an initialization process that is performed for each data source when the data source is added to a protection group.
• Replica volume: A volume on the DPM server that contains the replica for a protected data source.
• Custom volume: A volume that is not in the DPM storage pool and is specified to store the replica and recovery points for a protection group member.
• Dismount: To remove a removable tape or disc from a drive.
• DPM Alerts log: A log that stores DPM alerts as Windows events so that the alerts can be displayed in Microsoft System Center Operations Manager (SCOM).
• DPMDB.mdf: The filename of the DPM database, the SQL Server database that stores DPM settings and configuration information.
• DPMDBReaders group: A group, created during DPM installation, that contains all accounts that have read-only access to the DPM database. The DPMReport account is a member of this group.
• DPMReport account: The account that the Web and NT services of SQL Server Reporting Services use to access the DPM database. This account is created when an administrator configures DPM reporting.
• MICROSOFT$DPM$: The name that the DPM setup assigns to the SQL Server instance used by DPM.
• Microsoft$DPMWriter$ account: The low-privilege account under which DPM runs the DPM Writer service. This account is created during the DPM installation.
• MSDPMTrustedMachines group: A group that contains the domain accounts for computers that are authorized to communicate with the DPM server. DPM uses this group to ensure that only computers that have the DPM protection agent installed from a specific DPM server can respond to calls from that server.
• Protection configuration: The collection of settings that is common to a protection group; specifically, the protection group name, disk allocations, replica creation method, and on-the-wire compression.
• Protection group: A collection of data sources that share the same protection configuration.
• Protection group member: A data source within a protection group.
• Protected computer: A computer that contains data sources that are protection group members.
• Synchronization: The process by which DPM transfers changes from the protected computer to the DPM server, and applies the changes to the replica of the protected volume.
• Recovery goals: The retention range, data loss tolerance, and frequency of recovery points for protected data.
• Recovery collection: The aggregate of all recovery jobs associated with a single recovery operation.
• Recovery point: The date and time of a previous version of a data source that is available for recovery from media that is managed by DPM.
• Report database: The SQL Server database that stores DPM reporting information (ReportServer.mdf).
• ReportServer.mdf: In DPM, the filename for the report database—a SQL Server database that stores reporting information.
• Retention range: Duration of time for which the data should be available for recovery.