Summary
The article is intended to document the manual steps that are required to be performed on the NetApp Clustered Data ONTAP (CDOT) storage volume including (a) setting up the volume with pre-requisite conditions and (b) handling the switch between iSCSI and NFS transport protocol. NFS transport protocol is used by NetApp Open Systems Backup (NOSB) to support data movement. Note that in DPX release 4.3.3 (r430 PL 232), CDOT support was introduced using iSCSI protocol. Users should be familiar with the commands or NetApp manuals that describe how the above configuration can be performed.
Resolution
The document details the procedure to handle the switch between iSCSI and NFS based block backups to NetApp CDOT storage.
A. Below are the pre-requisites for setting the NetApp CDOT volume to qualify for NFS based transport backup method.
1. Each SVM that is intended for use with DPX Block backup must be configured as follows:
Create a custom DPX export policy with the following attributes set:
- Client match 0.0.0.0/0
- Superuser any
A screenshot of a custom export policy via NetApp On-Command Manager is below. The policy name is vs_dpx_export _policy.
2. NetApp CDOT volume must be configured with the following attributes:
- Security style must be mixed or UNIX. NTFS security style should not be selected
- Read/Write/Execute permissions must be 0777
- Export policy on the volume should be set to custom defined DPX export policy ( created in step 1 )
- Volume must be mounted at root of SVM namespace "/"
A screenshot of a NetApp CDOT volume created using the above attributes via NetApp On-Command Manager is below. The volume in this example is SS_newNFS_Vol.
3. From the CDOT cluster command line, run the following command on the SVM to which the CDOT backup is done.
nfs modify -mount-rootonly disabled -nfs-rootonly disabled -vserver <SVM_NAME>
B. Set the registry key on the DPX Client to switch from iSCSI to NFS.
a. Browse to the below registry key location: HKEY_LOCAL_MACHINE\SOFTWARE\Syncsort\BackupExpress\<hostname>\0
b. Add a new String value as: NIB_CDOT_BACKUP=NFS
C. If there is a forced switch of transport mode from iSCSI to NFS using the Registry key setting, then you must examine all qtrees for the client and reset the permissions recursively to 0777. For that, do an NFS mount of that NetApp volume to a Linux box and edit the permissions.
Set the recursive file permission on the qtree folder as: chmod -R 777 <Qtree folder corresponding to the block backup job >
For example, to change the permissions on the qtree folder, mount the NetApp CDOT volume to a Linux box.
If next incremental is to use NFS transport method, the permissions on the qtree may be modified as:
Alternatively, changing the permission can be done on NetApp side:
1. Run “volume qtree show -vserver [SVM name] -volume [Volume Name] -qtree [qtree Name] -fields unix-permissions” to find the permission
• For example, volume qtree show -vserver SVM-CS-tst01_g -volume wxk_iSCSI1 -qtree wxk_qtreeiSCSI1 -fields unix-permissions
• The output should appear like this:
vserver volume qtree unix-permissions
-------------- ---------- --------------- ----------------
SVM-CS-tst01_g wxk_iSCSI1 wxk_qtreeiSCSI1 ---rwxr-xr-x
2. To modify the permission
• Run “volume qtree modify -vserver [SVM name] -volume [Name of volume that contains the qtree] -qtree [qtree name] -unix-permissions 0777”
• For example, volume qtree modify -vserver SVM-CS-tst01_g -volume wxk_iSCSI1 -qtree wxk_qtreeiSCSI1 -unix-permissions 0777
3. To verify the change
• Run "volume qtree show -vserver [SVM name] –volume [Volume Name] -qtree [qtree Name] -fields unix-permissions"
• For example, volume qtree show -vserver SVM-CS-tst01_g -volume wxk_iSCSI1 -qtree wxk_qtreeiSCSI1 -fields unix-permissions
D. In order to continue backups to a SnapMirror target volume using the NFS method, ensure that the volume satisfies the pre-requisites mentioned in Section A.