Administrator Guide

than just backing up the first instance of the hard link files. In this case, a selective restore will always have the file 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
files.
Backing Up NAS Volume Data Using NDMP
The FluidFS cluster does not use a dedicated IP address for backup operations; any configured 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 off-peak times.
About this task
After you configure 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 42. 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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