Backing up volume data

Data structure of the backed up data

When you back up a source volume using SnapVault, the volume is backed up to a qtree on the secondary storage system; therefore, any qtrees in the source volume become directories in the destination qtree.

Reasons for backing up a volume using SnapVault

You might want to back up a volume to a qtree using SnapVault for one or more of the following reasons:

You want to back up a volume that contains many qtrees.
You want the Snapshot management that SnapVault provides.
You want to consolidate the data from several source volumes on a single destination volume.

Limitations to backing up a volume to a qtree

There are limitations to backing up a volume to a qtree. You should consider the following limitations before performing a volume-to-qtree backup:

You lose the qtree as a unit of quota management.
Quota information from the qtrees in the source volume is not saved when they are replicated as directories in the destination qtree.
You lose qtree security information.
If the qtrees in the source volume had different qtree security styles, those security styles are lost in the replication to the destination qtree and are replaced by the security style of the volume.
It is not a simple process to restore data.
SnapVault cannot restore the data back to a volume. When restoring data, what was a source volume is restored as a qtree.

See Restoring the qtree to the original volume structure for a process to restore data.
Volume-to-qtree backup is not supported for volumes containing Data ONTAP LUNs.

Initiating backup of primary system volume data

To replicate and protect volume data in a primary storage system, complete the following step.

Step	Action
1	From the secondary storage system, enter the following command: snapvault start -S prim_system:/vol/volume_name /vol/volume_name/qtree_name `-S` prim_system:/`vol`/volume_name specifies the volume on the primary storage system whose non-qtree data you want to backup. /`vol`/volume_name/qtree_name specifies the qtree in the secondary storage system where you want to store this data. Note The qtree that is specified for /`vol`/volume_name/qtree_name must not exist on the secondary system before you run the `snapvault start` command.

Step

Action

From the secondary storage system, enter the following command:

snapvault start -S prim_system:/vol/volume_name 
/vol/volume_name/qtree_name

-S prim_system:/vol/volume_name specifies the volume on the primary storage system whose non-qtree data you want to backup.

/vol/volume_name/qtree_name specifies the qtree in the secondary storage system where you want to store this data.

Note
The qtree that is specified for /vol/volume_name/qtree_name must not exist on the secondary system before you run the snapvault start command.

Example

systemB> snapvault start -S systemA:/vol/vol1 
/vol/vol4/vol1_copy

Result

SnapVault transfers the data in vol1 on primary systemA to the qtree called vol1_copy in vol4 on systemB (the secondary storage system). It also configures the qtree for future updates.

Restoring the qtree to the original volume structure

If you were to use the snapvault restore command, the source volume you backed up to a qtree is restored as a qtree on the primary storage system.

To restore the backed-up qtree to the original volume structure with multiple qtrees on the primary storage system, complete the following steps.

Step	Action
1	Re-create all of the qtrees in the volume on the primary storage system using the `qtree create` command. Example The following command creates a project_x qtree in the projs volume: pri_system> qtree create /vol/projs/project_x
2	Restore the data for each qtree using the `ndmpcopy` command. Example The following command restores data from the backed-up project_x directory on the secondary storage system to the re-created project_x qtree on the primary storage system. *pri_system> ndmpcopy -sa username:password* system2:/vol/vol1/projs/project_x /vol/projs/project_x**
3	Stop qtree updates and remove the qtree on the secondary storage system using the `snapvault stop` command. Example The following command removes the projs qtree from the secondary storage system: sec_system> snapvault stop /vol/vol1/projs
4	Reinitialize a baseline copy of each qtree to the secondary storage system using the `snapvault start` command. Example The following command reinitializes the SnapVault backup: snapvault start -S rdsystem:/vol/projs /vol/vol1/projs