NetApp Selective LUN Mapping
The following is based on Selective LUN Map. Additional information can be viewed at FAQ: Selective LUN mapping.
Selective LUN Map (SLM) reduces the number of paths from the host to the LUN. With SLM, when a new LUN map is created, the LUN is accessible only through paths on the node owning the LUN and its HA partner.
SLM enables management of a single igroup per host and also supports non-disruptive LUN move operations that do not require portset manipulation or LUN remapping.
Portsets can be used with SLM just as in previous versions of Data ONTAP to further restrict access of certain targets to certain initiators . When using SLM with portsets, LUNs will be accessible on the set of LIFs in the portset on the node that owns the LUN and on that node’s HA partner.
Beginning with Data ONTAP 8.3 SLM is enabled by default on all new LUN maps. For LUNs created prior to Data ONTAP 8.3, you can manually apply SLM by using the lun mapping remove-reporting-nodes command to remove the LUN reporting nodes and restrict LUN access to the LUN owning node and its HA partner.
Example
Beginning with Data ONTAP 8.3 SLM is enabled by default on all new LUN maps. For LUNs created prior to Data ONTAP 8.3, you can manually apply SLM by using the lun mapping remove-reporting-nodes command to remove the LUN reporting nodes and restrict LUN access to the LUN owning node and its HA partner.
More Information
How to determine whether SLM is enabled on a LUN map
If your environment has a combination of LUNs created in Data ONTAP 8.3 and LUNs transitioned into Data ONTAP 8.3 from previous versions, you might need to determine whether Selective LUN Map (SLM) is enabled on a specific LUN.
cluster::> lun mapping show -vserver <vserver> -fields reporting-nodes
cluster::> lun mapping show -vserver svm01 -fields reporting-nodes
| 6 entries were displayed. | |||
| vserver | path | igroup | reporting-nodes |
|---|---|---|---|
|
|
|
|
|
| svm01 | /vol/svr01_cv_app/svr01_cv_app | svr01 | cluster-03,cluster-04 |
| svm01 | /vol/svr01_cv_index/svr01_cv_index | svr01 | cluster-01,cluster-02 |
| svm01 | /vol/svr02_cv_app/svr02_cv_app | svr02 | cluster-03,cluster-04 |
| svm01 | /vol/svr02_cv_index/svr02_cv_index | svr02 | cluster-01,cluster-02 |
| svm01 | /vol/svr_san_boot/svr01 | svr01 | — |
| svm01 | /vol/svr_san_boot/svr02 | svr02 | — |
Decreasing mapped LUN paths with SLM for LUNs created prior to Data ONTAP 8.3
You can reduce the number of paths mapped to your LUNs by using Selective LUN Map (SLM). Reducing the number of LUN paths simplifies host side multipath management and ensures that the number of host paths to the LUN does not exceed the maximum supported by Data ONTAP.
- If you are modifying reporting nodes you must be in advanced mode
cluster::> set advanced
Warning: These advanced commands are potentially dangerous; use them only when directed to do so by NetApp personnel.
Do you want to continue? {y|n}: y
cluster::*> lun mapping add-reporting-nodes -vserver -path -igroup -local-nodes true
cluster::*> lun mapping show -vserver svm01 -fields reporting-nodes
| 6 entries were displayed. | |||
| vserver | path | igroup | reporting-nodes |
|---|---|---|---|
|
|
|
|
|
| svm01 | /vol/svr01_cv_app/svr01_cv_app | svr01 | cluster-03,cluster-04 |
| svm01 | /vol/svr01_cv_index/svr01_cv_index | svr01 | cluster-01,cluster-02 |
| svm01 | /vol/svr02_cv_app/svr02_cv_app | svr02 | cluster-03,cluster-04 |
| svm01 | /vol/svr02_cv_index/svr02_cv_index | svr02 | cluster-01,cluster-02 |
| svm01 | /vol/svr_san_boot/svr01 | svr01 | — |
| svm01 | /vol/svr_san_boot/svr02 | svr02 | — |
cluster::*> lun mapping add -vserver svm01 -path /vol/svr_san_boot/svr01 -igroup svr01 -local-nodes true
cluster::*> lun mapping show -vserver svm01 -fields reporting-nodes
| 6 entries were displayed. | |||
| vserver | path | igroup | reporting-nodes |
|---|---|---|---|
|
|
|
|
|
| svm01 | /vol/svr01_cv_app/svr01_cv_app | svr01 | cluster-03,cluster-04 |
| svm01 | /vol/svr01_cv_index/svr01_cv_index | svr01 | cluster-01,cluster-02 |
| svm01 | /vol/svr02_cv_app/svr02_cv_app | svr02 | cluster-03,cluster-04 |
| svm01 | /vol/svr02_cv_index/svr02_cv_index | svr02 | cluster-01,cluster-02 |
| svm01 | /vol/svr_san_boot/svr01 | svr01 | cluster-01,cluster-02 |
| svm01 | /vol/svr_san_boot/svr02 | svr02 | — |
Disable Selective LUN Map Cluster-wide
Can Selective LUN Map be disabled?
Selective LUN Map (SLM) is enabled by default. Run the following commands to disable LUN Map cluster-wide:
cluster::> set diag
Warning: These diagnostic commands are for use by NetApp personnel only.
Do you want to continue? {y|n}: y
cluster::*> options lun.reporting_nodes.enable off