Administrator Guide

To work around this problem, change the behavior during backup. If a backup is started with the DEREF_HARD_LINK environment
variable set to Y, the backup will back up all instances of the hard link les as if they were regular les, rather than just backing up the rst
instance of the hard link les. In this case, a selective restore will always have the le data. The disadvantage of this option is that backups
might take longer and more space is required to back up a data set with hard link les.
Backing Up NAS Volume Data Using NDMP
The FluidFS cluster does not use a dedicated IP address for backup operations; any congured client network address can be used. Data is
sent over Ethernet. Multiple NDMP backup and restore sessions can run at the same time with a maximum of 48 sessions per NAS
controller. To minimize the impact of NDMP backup processing on system performance, schedule NDMP operations during o-peak times.
About this task
After you congure NDMP in a FluidFS cluster, the NDMP server monitors the client network for backup requests from the DMA servers.
The DMA server then accesses (mounts) the NAS volumes that it intends to back up and initiates the backup operations.
Figure 48. NDMP Backups
Keep the following considerations in mind when backing up NAS volume data using NDMP:
• NDMP does not provide high availability (HA). If a backup session is interrupted due to connection loss, the session is terminated.
• Manually deleting the temporary snapshot for the current backup session is not allowed and will immediately terminate the session.
• If a backup session is terminated with an error, the temporary snapshot might be left in place, and the system will delete the snapshot
automatically.
The following steps outline the process for backing up NAS volume data with NDMP:
Steps
1 The DMA server creates a connection to the FluidFS cluster IP address.
2 The NDMP server on the FluidFS cluster creates a temporary snapshot of each NAS volume that the DMA server designated for
backup. Alternatively, when performing a backup of replication target NAS volumes, the FluidFS cluster does not create a dedicated
NDMP snapshot. Instead, it uses the base replica snapshot from the last successful replication.
Temporary NDMP snapshots are named using the following format: ndmp_backup_session_id_controller_number
3 The NDMP server copies the NAS volume data to the DMA server.
4 After receiving the data, the DMA server moves the data to a storage device, such as a local disk or tape device.
5 After the backup completes, the NDMP server deletes the temporary snapshots.
NDMP Environment Variables
NDMP environment variables control the behavior of the NDMP server for each backup and restore session.
To determine whether the DMA server supports setting these environment variables, refer to the documentation for your DMA server. If
the DMA server cannot set a particular environment variable, the NDMP server operates with the default value.
The following table summarizes the supported environment variables.
FluidFS Administration
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