Managing LUNs

Management tasks

You can perform the following tasks to manage LUNs.

Manage LUN maps
Map a LUN to an initiator group to make it available to the initiators in the initiator group
Unmap a LUN from an initiator group to make it unavailable to the initiators in the initiator group
Bring a LUN online to make it available for block protocol access (or SAN)
Take a LUN offline to make it available for file protocol access (or NAS)
Remove (destroy) a LUN
Access a LUN with NAS protocols

How to manage LUN maps

To support a large number of hosts and to enforce access control, Data ONTAP maintains a separate map for each initiator group. This map controls which LUN is accessible to a given initiator group at a given LUN ID.

After you create a LUN, you must map it to the specific initiator group for it to be accessible to the hosts in that initiator group. Use the following guidelines when mapping LUNs:

You can map two different LUNs to the same LUN ID for two different initiator groups without having a conflict.
You can map a LUN only once to an initiator group.
You cannot map two LUNs to an initiator group at the same LUN ID.

Using the lun map command automatically brings a LUN online. The lun online and lun offline commands enable and e block protocol accesses while preserving mappings.

Mapping a LUN to an initiator group

The LUN ID is mapped to the initiators (hosts) in the initiator group. You can specify a LUN ID or you can use the number automatically assigned by Data ONTAP, which begins with 0 and increments by 1 every time a new LUN ID needs to be assigned. Network Appliance recommends that you allow Data ONTAP to automatically assign LUN IDs.

To allow Data ONTAP to map a LUN to an initiator group at an automatically assigned LUN ID, complete the following step.

Step	Action
1	Enter the following command: *`lun map` lun-path igroup* `LUN_ID`** Example l`un map /vol/vol1/qtree1/lun3 solhost2` Result Data ONTAP maps lun3 to the initiator group solhost2 at the first available LUN ID, in this case LUN ID 0.

Unmapping a LUN from an initiator group

To remove the mapping of a LUN from an initiator group, complete the following steps.

Step	Action
1	Enter the following command: lun offline lun-path Example `lun offline /vol/vol1/lun1`
2	Enter the following command: *lun unmap lun-path igroup* LUN_ID** Example `lun unmap /vol/vol1/lun1 solaris-igroup0 0`

Step

Action

Enter the following command:

lun offline lun-path

Example

lun offline /vol/vol1/lun1

Enter the following command:

lun unmap lun-path igroup LUN_ID

Example

lun unmap /vol/vol1/lun1 solaris-igroup0 0

Bringing a LUN online

To bring one or more LUNs online, complete the following step.

Step	Action
1	Enter the following command: lun online lun-path [lun-path ...] Example `lun online /vol/vol1/lun0`

Taking a LUN offline

Taking a LUN offline makes it unavailable for block protocol access; however, you can write to an offline LUN using NAS protocols. To take a LUN offline, complete the following step.

Step	Action
1	Enter the following command: lun offline lun-path [lun-path ...] Example `lun offline /vol/vol1/lun0`

Removing a LUN

To remove one or more LUNs, complete the following step.

Step	Action
1	Remove one or more LUNs by entering the following command: *lun destroy [-f] lun-path* [lun-path ...]** -f forces the lun destroy command to execute even if the LUNs specified by one or more lun-paths are mapped or are online. Without the -f parameter, you must first take the LUN offline and unmap it, and then enter the `lun destroy` command.

Step

Action

Remove one or more LUNs by entering the following command:

lun destroy [-f] lun-path [lun-path ...]

-f forces the lun destroy command to execute even if the LUNs specified by one or more lun-paths are mapped or are online.

Without the -f parameter, you must first take the LUN offline and unmap it, and then enter the lun destroy command.

Accessing a LUN with NAS protocols

When you create a LUN, it can only be accessed with SAN protocols by default. However, you can make a LUN available to a host using NAS protocols if NAS protocols are licensed and enabled on the filer. The usefulness of accessing a LUN over NAS protocols is host application-dependent.

Note
A LUN cannot be extended or truncated using NFS or CIFS protocols.

If you want to write to a LUN over NAS protocols, you must take the LUN offline or unmap it to prevent overwriting data in the LUN using the SAN protocol. To make a LUN accessible to a host using a NAS protocol, complete the following step.

Step	Action
1	Determine whether you want to read or write to the LUN over the NAS protocol and take appropriate action: If you want read access, the LUN can remain online. If you want write access, ensure that the LUN is offline or unmapped.
2	Enter the following command: *`lun share` lun-path* `{none\|read\|write\|all}`** Example lun share /vol/vol1/qtree1/lun2 read Result The LUN is now readable over NAS.

Step

Action

Determine whether you want to read or write to the LUN over the NAS protocol and take appropriate action:

If you want read access, the LUN can remain online.
If you want write access, ensure that the LUN is offline or unmapped.

Enter the following command:

lun share lun-path {none|read|write|all}

Example

lun share /vol/vol1/qtree1/lun2 read

Result

The LUN is now readable over NAS.