Microsoft Exchange Server backup methods
Depending on your Exchange Server environment, you can run only full backups, full plus incremental backups, or full plus differential backups. Your backup strategy might also include backing up data to IBM Spectrum Protect™ or local shadow volumes.
As you consider Exchange Server backup methods, understand all aspects of Exchange Server disaster recovery and the backup recommendations that Microsoft provides.
- Do not implement incremental and differential backups together.
- If you choose a strategy that involves incremental or differential backups, you must disable circular logging on the databases of the Exchange Server.
Full backup method
Use the full backup method during low usage times because a full backup can take a long time to run. However, the restore process is the most efficient because only the most recent full backup is restored.
Full backup plus incremental backup method
Use the full backup plus incremental backup method when the normal backup schedule or network capacity cannot support a full backup.
To minimize the effect on the backup schedule and network traffic during peak times, you can run a periodic full backup, followed by a series of incremental backups. For example, you can schedule full backups on the weekend and incremental backups during the week. You can run full backups during low usage times and when increased network traffic can be tolerated.
If you use this backup strategy, modify the IBM Spectrum Protect storage management policies to ensure that all incremental backups are collocated on the IBM Spectrum Protect server. In this way, you can improve data restore performance by reducing the number of media mounts that are necessary to restore a series of incremental backups.
Full backup plus differential backup method
Use the full backup plus differential backup method if your backup schedule and network capacity can facilitate backing up all transaction logs that accumulate between full backup operations. This strategy requires that only one differential backup plus the last full backup be transferred to complete a restore operation. However, the same amount of data must be transferred in the differential image, as in the series of incremental backup operations.
Therefore, a full backup plus differential backup policy increases network traffic and IBM Spectrum Protect storage usage. This policy assumes that the differential backups are processed as often as the incremental backups.
Consider the potential advantages and whether you can justify the additional resources that are necessary to resend all prior transaction logs with each subsequent differential backup.
IBM Spectrum Protect backups versus local shadow volumes backups
When you create a policy for your backups, you must choose whether to back up data to IBM Spectrum Protect storage versus VSS disks. Data backups to IBM Spectrum Protect typically takes longer to process than backups to local shadow volumes.
Backing up Exchange Server data to IBM Spectrum Protect is necessary when long-term storage is required. For example, saving Exchange Server data on tape for archival purposes requires long-term storage. IBM Spectrum Protect backups are also necessary for disaster recovery situations when the disks that are used for local backups are unavailable.
By maintaining multiple backup copies on IBM Spectrum Protect server storage, a point-in-time copy is available if backups on the local shadow volumes become corrupted or deleted.
Local shadow volumes
When you back up data to local shadow volumes, ensure that sufficient local storage space is assigned to the local shadow volumes. Create different sets of policies for backups to both local shadow volumes and to IBM Spectrum Protect server storage. If you use a VSS provider other than the Windows VSS System Provider, follow the backup recommendations of the VSS provider.
You can run backups to local shadow volumes by time and backup versions. It is more effective to base policy for local backups on version limits because local snapshots are created more frequently and VSS storage provisioning and space limitations apply. In Database Availability Group (DAG) environments, all of the DAG members must use the same local VSS policy.
Environment and storage resources also impact how many backup versions you can maintain on local shadow volumes for VSS fast restore and VSS instant restore operations, and on IBM Spectrum Protect server for VSS restore operations.