Handling Backup Copy Job Issues

Being a scheduled activity, the backup copy job may fail to run as expected. Veeam Backup & Replication automatically handles some issues that can occur with the backup copy job.

Short Synchronization Intervals

In some cases, Veeam Backup & Replication may fail to transport the restore point within the synchronization interval of the backup copy job. This can happen, for example, if the synchronization interval is too short and is not sufficient for the amount of data to be copied.

Veeam Backup & Replication handles this situation differently for the first and subsequent synchronization intervals.

• The first synchronization interval always produces a full backup file — the starting point in the backup chain. If Veeam Backup & Replication fails to copy data for the full backup file during the first synchronization interval, it marks the job session as finished with the Warning status. During the next synchronization interval, Veeam Backup & Replication attempts to copy data for the full backup file in the following manner:

1. When a new synchronization interval begins, the restore point that was previously copied no longer corresponds to the restore point selection rules. That is, the time of the restore point creation falls out of the search scope. For this reason, Veeam Backup & Replication waits for a new restore point to appear on the source backup repository.
2. When a new restore point appears on the source backup repository, Veeam Backup & Replication detects what data blocks still need to be copied to make up a full backup file on the target backup repository, and copies these data blocks.
   
   This process continues until there is a full backup file on the target backup repository.

• At subsequent synchronization intervals, Veeam Backup & Replication copies incremental restore points. If Veeam Backup & Replication fails to transport an incremental restore point, it marks the synchronization task as failed. Veeam Backup & Replication waits for the expiration of the synchronization interval; after that, Veeam Backup & Replication marks the job session as finished with the Error status.

Veeam Backup & Replication does not mark the backup copy job session with the Error status if the source backup job has not started during the synchronization interval of the backup copy job (that is, the backup copy job has nothing to copy to the target backup repository).

Simultaneous Use of Backup Files

In some cases, the source backup job and backup copy job may overlap. Such situation can occur, for example, if the source backup job needs to transform the source backup chain.

If a specific task in the backup copy job locks the source backup chain to read VM data from it, and the source backup job that needs to write data to this backup chain starts at this moment (for example, for reverse incremental backup), the task in the backup copy job is put on hold. The backup copy job can continue processing other tasks that use other sources (for example, backup files created by other backup jobs). After the source backup job releases the backup chain, the backup copy job resumes processing VMs in this backup chain.

Change of the Synchronization Interval Start Time

If you have selected to run a backup copy job with a daily synchronization interval, you must define the start time of the synchronization interval. However, you may want to change the start time afterwards. After the start time change, Veeam Backup & Replication behaves in the following manner:

1. Veeam Backup & Replication finishes the current synchronization interval running according to the 'old' start time value as usual.
2. After the current synchronization interval is over, Veeam Backup & Replication immediately starts the synchronization interval, not waiting for the 'new' start time point to come. At that, Veeam Backup & Replication “stretches” the started interval: the interval lasts for the time remaining till the new start time plus the time of the synchronization interval itself.
3. All subsequent synchronization intervals are created and started in a regular manner by the new schedule.

For example, when you first created a backup copy job, you set a daily synchronization interval with the start time at 8 AM. After that, you changed the start time to 10 AM. In this case, Veeam Backup & Replication will first finish the synchronization interval that is currently running — that is, the synchronization interval that was started at 8 AM — as usual. After that, it will immediately start a new synchronization interval. This interval will run for 26 hours — from 8 AM of the current day until 10 AM of the next day. All subsequent synchronization intervals will be started at 10 AM every day.

The first synchronization interval that is run after the start time change is typically longer than a regular one. This happens because of the synchronization interval “stretch” mentioned above. To start the synchronization process right away, you can use the Sync Now option after you change the start time value. In this case, Veeam Backup & Replication will behave in the following manner:

1. When you start the synchronization process manually, Veeam Backup & Replication forcibly finishes the current synchronization interval and begins a new synchronization interval according to the new start time value. This synchronization interval lasts until a new synchronization interval by the new schedule must be started.
2. All subsequent synchronization intervals are created and started in a regular manner.

As a result, the first synchronization interval after the start time change will begin immediately.

For example, when you first created a backup copy job, you set a daily synchronization interval with the start time at 8 AM. After that, you changed the start time to 10 AM. On the start time change, you started the manual synchronization process at 1 PM. In this case, Veeam Backup & Replication will finish the current synchronization interval — that is, the synchronization interval that was started at 8 AM — immediately at 1 PM. After that, it will start a new synchronization interval. This interval will run for 21 hours — from 1 PM of the current day until 10 AM of the next day. All subsequent synchronization intervals will be started at 10 AM every day.