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Data storage

Updated: November 1, 2013

Applies To: System Center 2012 - Data Protection Manager, System Center 2012 R2 Data Protection Manager, System Center 2012 SP1 - Data Protection Manager

You can back up data for workloads protected by to disk, tape, or the Windows Azure cloud. When you need to restore data recovery is fast and simple. You identify the data, and DPM locates the data and retrieves it.

This topic discusses storage options for DPM backups. For more information about how DPM protects data with backup and replication, see Data protection.

Your backup and storage settings will depend on the protection requirements for your organization, and includes the following considerations:

  • How much data your organization can afford to lose. Realistically, not all data is equally valuable. You should weigh the impact of loss against the costs of protection.

  • How quickly recovered data must be available. Different types of data will have different recovery point objectives (RPO). Recovery of data that is critical to ongoing operations is typically more urgent than routine data.

  • How long your organization must maintain data. Long-term storage might be necessary for business operations, depending on the type and contents of the data. For example your organization might be subject to legal requirements for data retention.

  • How much your organization can spend on data protection. When deciding how much to invest in data protection, you should include the cost of hardware and media, as well as the personnel costs for administration, management, and support.

Types of backup storage

The following table summarizes the different types of storage available for workloads protected by DPM.

 

Storage type Details Characteristics

Tape

Backup data from protected computers or workloads directly to tape

  • Used for long-term storage.

  • You can use tape for short-term storage of file data (volumes, shares, folders). For workload data (Exchange, SQL Server, SharePoint, Hyper-V) you can only use disk or Windows Azure Backup (SQL Server and Hyper-V workloads only) for short-term backup.

  • Can be stored offsite which mitigates data loss in case of disaster.

  • Easy to increase storage capacity by adding more tapes.

  • Data recovery might be slow and cumbersome.

  • Tape backup might require manual interventions such as manual tape rotations.

  • Tape backup will require a compatible tape library. See Compatible Tape Libraries for System Center 2012 DPM.

  • Tape library or standalone tape drive must be physically attached to the DPM server. The tape library can be direct SCSI attached or SAN.

Disk

Backup data from protected computers or workloads to disk for short-term storage

  • Used for short-term storage. Backing up to disk alone does not provide a simple solution for long-term or offsite storage.

  • Quick method of data backup

  • Ability to have redundancy to handle failure using technologies such as RAID.

  • Less manual intervention, such as changing tapes. 

  • Maximum retention for disk is 448 days.

  • Backup occurs with no impact on running workloads.

Windows Azure

Use for short-term storage in conjunction with disk

  • Provides off-site solution for short-term storage.

  • Can only be used as storage for Hyper-V, SQL Server, and file server data protected by DPM.

  • Windows Azure Backup can only be used to backup data on servers installed with Windows Server 2012 R2, Windows Server 2012, or Windows Server 2008 R2 with SP1, and running DPM in System Center 2012 SP1 or System Center 2012 R2.

  • Maximum storage retention period of 120 days with one synchronization per day. You can perform up to two synchronizations, but two synchronizations will reduce retention time to 60 days.

  • Can only be used as a short-term backup solution in conjunction with disk storage. You can’t configure DPM to back up to Windows Azure only.

You can integrate different types of storage together:

  • Disk-to-disk-to-tape backup (D2D2T)— Backup long-term data to tape and short-term data to disk. This method provides a solution for both short-term and long-term backup.

  • Disk-to-disk-to-tape backup (D2D2T) + Windows Azure Backup—This method provides more resilience than D2D2T alone since it ensures that your short-term storage is offsite as well as onsite.

How DPM uses standalone tape drives

For stand-alone tape drives, System Center 2012 – Data Protection Manager (DPM) does the following for each protection group:

  • Appends all short-term backups to a single tape.

  • Appends all long-term backups to a single tape that is different from the short-term backup tape.

When a tape fills up, DPM raises an alert to add a new free tape.

How DPM uses tape libraries

System Center 2012 – Data Protection Manager (DPM) can allocate two or more tapes for each protection group. All the data sources in a protection group will always append to the same tape regardless of whether short-term or long-term protection is specified.

If the user specifies the allocation of more than one drive while creating the protection group, the data sources will be split across tapes. For example, if there are five data sources and a drive with a maximum limit of two sources, DPM may write three data sources on one tape and two on another. Depending on the size of the data sources, other scheduled backup jobs to tape in other protection groups, and the number of tape drives available at the time, you may find an uneven distribution of data sources going to the various tapes.

The following table shows how the backup mode influences the number of tapes required for short-term protection.

 

Backup mode

Tapes required

Short-term tape "full" option

Backup jobs will require a free tape for each scheduled job.

Short-term tape "full and incremental" option

The full backup will require a free tape for each scheduled job, and the incremental backup for all data sources will be appended to a single separate tape.

As tapes fill up, new free tapes will be allocated.

When the next full backup occurs, it will require another free tape, and subsequent incremental backups will be appended to another free tape.

Example: If a full backup is scheduled weekly and incremental backups are scheduled daily, then the first full backup will go to a new free tape and all subsequent incremental backups for six days will be appended to another new free tape.

Note that if a full backup job fails before it is completed, all the subsequent incremental jobs will use the existing tape that has valid previous incremental backups. Note that If the customer manually triggers two individual “create recovery point (tape)” actions for two protection group members, DPM will create two tape backup jobs and will need two tapes to store tape backup. However, if two protection group members are selected (multi-select in Protection view) and “create recovery point (tape)” is triggered, DPM will use a single tape. This is designed to co-locate the data for selected protection group members for ad-hoc tape backups onto the same tape.

For long-term protection a tape will be allocated for each full backup job. The reason long-term full tape backups are on separate tapes is because they are meant to be stored offline, and possibly offsite. So each long-term backup recovery point created will always be on a new tape.

Available free tapes will be decremented as tapes are allocated to either short-term or long-term tape jobs. However, for short-term protection, creating a new recovery point will succeed even when the "available free tapes = 0" because DPM will append the backup job to the tape that is currently in use. Only long-term tape backups require a new tape each time, and these backups will issue an alert if no tapes are available.

You cannot free or erase a tape that contains valid recovery points from any protected source. Before you can free a tape, you must perform one of the following steps:

  • Remove the sources from the protection group and choose to expire recovery points on the tape.

  • Change the protection group’s options and clear the tape protection options. Then, under Inactive protection for previously protected data, right-click each data source and select Remove inactive protection.

To restore data from an expired tape, mark the tape as free, then unmark the tape as free, and then recatalog the tape.

Next steps

Plan for data storage—After you understand basic storage concepts, you can start planning your storage requirements.

See Also

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For additional resources, see Information and Support for System Center 2012.

Tip: Use this query to find online documentation in the TechNet Library for System Center 2012. For instructions and examples, see Search the System Center 2012 Documentation Library.
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