Backing up data to tape
Structure of SAN backups
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
NetApp strongly recommends 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 filers.
The following diagram shows a SAN setup that uses two applications hosts and a clustered pair of filers.
Volumes on the iSCSI host can consist of a single LUN mapped from the filer or multiple LUNs using a volume manager.
Prior to creating a snapshot, you must quiesce the application or file system using the LUN (which flushes the host filer system buffers to disk), so that the snapshot is consistent with regard to the application.
Backing up a single LUN to tape
To map a LUN within a snapshot to the backup server for backup, the snapshot must be made writable.
To map a LUN within a snapshot 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:
igroup create -i [-t ostype] group [node ...]
Example
igroup create -i -t windows payroll_server
iqn.1991-05.com.microsoft:eng1
Result
Data ONTAP creates an igroup with -i, the iSCSI option, the operating system Windows, the name payroll, and the node name iqn.1991-05.com.microsoft:eng1.
|
|
2 |
Enter the following command to create a 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 LUN to the igroup with a SCSI ID:
lun map lun-path initiator-group scsi-lun
Example
lun map /vol/vol1/qtree_1/payroll_lun
payroll_server 1
Result
Data ONTAP maps the /vol/vol_name/qtree_1/payroll_lun LUN to the payroll_server igroup with a LUN ID of 1.
|
|
4 |
Save the contents of host file system buffers to disk using the command provided by your host operating system, or by using SnapDrive 2.0 or later for Windows systems.
|
|
5 |
Create a snapshot by using SnapDrive 2.0 for Windows systems, or enter the following command for non-Windows systems:
snap create volume_name snapshot_name
Example
snap create vol1 payroll_backup
|
|
6 |
Enter the following command to create a new LUN in the active file system so that it can be mapped to the backup server from the existing snapshot:
lun create -b snapshot lun-path lun-path
Example
lun create -b
vol/vol1/.snapshot/payroll_backup/qtree_1/payroll_lun
/vol/vol1/qtree_1/payroll_backup_lun
|
|
7 |
Enter the following command to map the new LUN you created to the backup host:
(backup_server is an igroup that already exists for the backup host.)
lun map lun-path initiator-group scsi-lun
Example
lun map /vol/vol_name/qtree_1/payroll_lun
payroll_server 1
Result
Data ONTAP maps the LUN /vol/vol_name/qtree_1/payroll_lun to the igroup payroll_server with a SCSI ID of 1.
|
|
8 |
Back up the data in the new LUN from the backup host to tape using your SAN backup application.
|
|
9 |
Take the backup LUN offline by entering the following command:
lun offline /vol/vol_name/qtree_name/lun_name
Example
lun offline /vol/vol1/qtree1/payroll_backup_lun
|
|
10 |
Remove the snapshot by entering the following command:
snap delete volume_name lun_name
Example
snap delete vol1 payroll_backup
|
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Part No. 210-00571
File: c5data7.htm
Last updated: 11/21/03 17:08:06