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Backing up data to tape

Structure of SAN backups  Top

In most cases, backup of SAN systems to tape takes place through a separate backup host to avoid performance degradation on the application host.

Note
It is strongly recommended that you keep SAN and NAS data separated for backup purposes. Configure volumes as SAN-only or NAS-only and configure qtrees within a single volume as SAN-only or NAS-only.

From the point of view of the SAN host, LUNs can be confined to a single WAFL volume or qtree or spread across multiple WAFL volumes, qtrees, or storage systems.

The following diagram shows a SAN setup that uses two applications hosts and a clustered pair of storage systems.

Volumes on a host can consist of a single LUN mapped from the storage system or multiple LUNs using a volume manager, such as VxVM on HP-UX systems.

Backing up a single LUN to tape  Top

To map a LUN within a Snapshot copy for backup, complete the following steps.

Note
Steps 4, 5, and 6 can be part of your SAN backup application's pre-processing script. Steps 9 and 10 can be part of your SAN backup application's post-processing script.

Step

Action

1

Enter the following command to create an igroup for the production application server:

igroup create -f [-t ostype] group [node ...]

Example

igroup create -f -t windows payroll_server 
10:00:00:00:c3:4a:0e:e1

Result

Data ONTAP creates an igroup called payroll_server, which includes the WWPN (10:00:00:00:c3:4a:0e:e1) of the Windows application server used in the production environment.

2

Enter the following command to create the production LUN:

lun create -s size [-t type] lun_path

Example

lun create -s 48g -t windows 
/vol/vol1/qtree_1/payroll_lun

Result

Data ONTAP creates a LUN with a size of 48 GB, of the type Windows, and with the name and path /vol/vol1/qtree_1/payroll_lun.

3

Enter the following command to map the production LUN to the igroup that includes the WWPN of the application server.

lun map lun_path initiator-group LUN_ID

Example

lun map /vol/vol1/qtree_1/payroll_lun 
payroll_server 1

Result

Data ONTAP maps the production LUN (/vol/vol_name/qtree_1/payroll_lun) to the payroll_server igroup with a LUN ID of 1.

4

From the host, discover the new LUN, format it, and make the file system available to the host. For information about these procedures, see the documentation that came with your Host Support Kit or Host Attach Kit.

5

When you are ready to do backup (usually after your application has been running for some time in your production environment), save the contents of host file system buffers to disk using the command provided by your host operating system, or by using SnapDrive for Windows or UNIX systems.

6

Create a Snapshot copy by entering the following command:

snap create volume_name snapshot_name

Example

snap create vol1 payroll_backup
7

Enter the following command to create a clone of the production LUN:

lun clone create clone_lunpath -b parent_lunpath 
parent_snap

Example

lun clone create 
/vol/vol1/qtree_1/payroll_lun_clone -b 
/vol/vol1/qtree_1/payroll_lun payroll_backup
8

Create an igroup that includes the WWPN of the backup server.

igroup create -f [-t ostype] group [node ...]

Example

igroup create -f -t windows backup_server 
10:00:00:00:d3:6d:0f:e1

Result

Data ONTAP creates an igroup that includes the WWPN (10:00:00:00:d3:6d:0f:e1) of the Windows backup server.

9

Enter the following command to map the LUN clone you created in Step 7 to the backup host:

lun map lun_path initiator-group LUN_ID

Example

lun map /vol/vol1/qtree_1/payroll_lun_clone 
backup_server 1

Result

Data ONTAP maps the LUN clone (/vol/vol1/qtree_1/payroll_lun_clone) to the igroup called backup_server with a SCSI ID of 1.

10

From the host, discover the new LUN, format it, and make the file system available to the host. For information about these procedures, see the documentation that came with your Host Support Kit or Host Attach Kit.

11

Back up the data in the LUN clone from the backup host to tape by using your SAN backup application.

12

Take the LUN clone offline by entering the following command:

lun offline /vol/vol_name/qtree_name/lun_name

Example

lun offline /vol/vol1/qtree_1/payroll_lun_clone
13

Remove the LUN clone by entering the following command:

lun destroy lun_path

Example

lun destroy /vol/vol1/qtree_1/payroll_lun_clone
14

Remove the Snapshot copy by entering the following command:

snap delete volume_name lun_name

Example

snap delete vol1 payroll_backup

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