Software-based disk ownership

About software-based disk ownership

Software-based disk ownership software assigns ownership of a disk to a specific storage system by writing software ownership information on the disk rather than by using the topology of the storage system's physical connections. Software-based disk ownership is implemented in storage systems where a disk shelf can be accessed by more than one storage system. Configurations that use software-based disk ownership include

FAS270 storage systems
Any storage system with a SnapMover license
Clusters configured for SnapMover vFiler^TM migration. For more information, see the section on the SnapMover vFiler no copy migration feature in the MultiStore Management Guide.
V-Series arrays. For more information, see the section on SnapMover in the V-Series Systems Software Setup, Installation, and Management Guide.
FAS900 series or higher storage systems configured with SharedStorage

FAS270 storage systems

The NetApp FAS270 and FAS270c storage systems consist of a single disk shelf of 14 disks and either one internal system head (on the FAS270) or two clustered internal system heads (on the FAS270c) . By design, a disk located on this common disk shelf can, if the storage system has two system heads, be assigned to the ownership of either system head. The ownership of each disk is ascertained by an ownership record written on each disk.

NetApp delivers the FAS270 and FAS270c storage systems with each disk preassigned to the single FAS270 internal system head or preassigned to one of the two FAS270c system heads.

If you add one or more disk shelves to an existing FAS270 or FAS270c storage system, you might have to assign ownership of the disks contained on those shelves.

Software-based disk ownership tasks

You can perform the following tasks:

Display disk ownership
Assign disks
Modify disk assignments
Re-use disks that are configured for software-based disk ownership
Erase software-based disk ownership prior to removing a disk
Automatically erase disk ownership information
Undo accidental conversion to software-based disk ownership

Displaying disk ownership

To display the ownership of all disks, complete the following step.

Step	Action
1	Enter the following command to display a list of all the disks visible to the storage system, whether they are owned or not. sh1> `disk show -v`

Note
You must use disk show to see unassigned disks. Unassigned disks are not visible using higher level commands such as the sysconfig command.

Sample output

The following sample output of the disk show -v command on an FAS270c shows disks 0b.16 through 0b.29 assigned in odd/even fashion to the internal cluster nodes (or system heads) sh1 and sh2. The fourteen disks on the add-on disk shelf are still unassigned to either system head.

sh1> disk show -v

 DISK      OWNER            POOL   SERIAL NUMBER

 --------- ---------------  -----  -------------

 0b.43     Not Owned        NONE   41229013

 0b.42     Not Owned        NONE   41229012

 0b.41     Not Owned        NONE   41229011

 0b.40     Not Owned        NONE   41229010

 0b.39     Not Owned        NONE   41229009

 0b.38     Not Owned        NONE   41229008

 0b.37     Not Owned        NONE   41229007

 0b.36     Not Owned        NONE   41229006

 0b.35     Not Owned        NONE   41229005

 0b.34     Not Owned        NONE   41229004

 0b.33     Not Owned        NONE   41229003

 0b.32     Not Owned        NONE   41229002

 0b.31     Not Owned        NONE   41229001

 0b.30     Not Owned        NONE   41229000

 0b.29     sh1 (84165672)   Pool0  41226818

 0b.28     sh2 (84165664)   Pool0  41221622

 0b.27     sh1 (84165672)   Pool0  41226333

 0b.26     sh2 (84165664)   Pool0  41225544

 0b.25     sh1 (84165672)   Pool0  41221700

 0b.24     sh2 (84165664)   Pool0  41224003

 0b.23     sh1 (84165672)   Pool0  41227932

 0b.22     sh2 (84165664)   Pool0  41224591

 0b.21     sh1 (84165672)   Pool0  41226623

 0b.20     sh2 (84165664)   Pool0  41221819

 0b.19     sh1 (84165672)   Pool0  41227336

 0b.18     sh2 (84165664)   Pool0  41225345

 0b.17     sh1 (84165672)   Pool0  41225446

 0b.16     sh2 (84165664)   Pool0  41201783

Additional disk show parameters are listed below.

disk show parameters	Information displayed
disk show -a	Displays all assigned disks
disk show -n	Displays all disk that are not assigned
disk show -o ownername	Displays all disks owned by the storage system or system head whose name is specified by ownername
disk show -s sysid	Displays all disks owned by the storage system or system specified by its serial number, sysid
disk show -v	Displays all the visible disks

Assigning disks

To assign disks that are currently labeled "not owned," complete the following steps.

Step	Action
1	Use the `disk show -n` command to view all disks that do not have assigned owners.
2	Use the following command to assign the disks that are labeled "Not Owned" to one of the system heads. If you are assigning unowned disks to a non-local storage system, you must identify the storage system by using either the `-o` ownername or the `-s` sysid parameters or both. *disk assign {disk_name* \|all\| -n count} [-p pool] [-o ownername] [-s sysid] [-c block\|zoned] [-f]** disk_name specifies the disk that you want to assign to the storage system or system head. `all` specifies all of the unowned disks are assigned to the storage system or system head. `-n` count specifies the number of unassigned disks to be assigned to the storage system or system head, as specified by `count`. `-p` pool specifies which SyncMirror pool the disks are assigned to. The value of pool is either 0 or 1. `-o` ownername specifies the storage system or the system head that the disks are assigned to. `-s` sysid specifies the storage system or the system head that the disks are assigned to. `-c` specifies the checksum type (either block or zoned) for a LUN in V-Series systems. `-f` must be specified if the storage system or system head already owns the disk. Example The following command assigns six disks on the FAS270c to the system head sh1: sh1> `disk assign 0b.43 0b.41 0b.39 0b.37 0b.35 0b.33` Result The specified disks are assigned as disks to the system head on which the command was executed.
3	Use the `disk show -v` command to verify the disk assignments that you have just made.

Step

Action

Use the disk show -n command to view all disks that do not have assigned owners.

Use the following command to assign the disks that are labeled "Not Owned" to one of the system heads. If you are assigning unowned disks to a non-local storage system, you must identify the storage system by using either the -o ownername or the -s sysid parameters or both.

disk assign {disk_name |all| -n count} [-p pool] [-o 
ownername] [-s sysid] [-c block|zoned] [-f]

disk_name specifies the disk that you want to assign to the storage system or system head.

all specifies all of the unowned disks are assigned to the storage system or system head.

-n count specifies the number of unassigned disks to be assigned to the storage system or system head, as specified by count.

-p pool specifies which SyncMirror pool the disks are assigned to. The value of pool is either 0 or 1.

-o ownername specifies the storage system or the system head that the disks are assigned to.

-s sysid specifies the storage system or the system head that the disks are assigned to.

-c specifies the checksum type (either block or zoned) for a LUN in V-Series systems.

-f must be specified if the storage system or system head already owns the disk.

Example

The following command assigns six disks on the FAS270c to the system head sh1:

sh1> disk assign 0b.43 0b.41 0b.39 0b.37 0b.35 0b.33

Result

The specified disks are assigned as disks to the system head on which the command was executed.

Use the disk show -v command to verify the disk assignments that you have just made.

After you have assigned ownership to a disk, you can assign that disk to the aggregate on the storage system that owns it, or leave it as a spare disk on that storage system.

Note
You cannot download firmware to unassigned disks.

Modifying disk assignments

You can also use the disk assign command to modify the ownership of any disk assignment that you have made. For example, on the FAS270c, you can reassign a disk from one system head to the other. On either the FAS270 or FAS270c storage system, you can change an assigned disk back to "Not Owned" status.

Attention
You should only modify disk assignments for spare disks. Disks that have already been assigned to an aggregate cannot be reassigned without endangering all the data and the structure of that entire aggregate.

To modify disk ownership assignments, complete the following steps.

Step	Action
1	View the spare disks whose ownership can safely be changed by entering the following command: `aggr status -r`
2	Use the following command to modify assignment of the spare disks. disk assign {disk1 [disk2] [...]\|-n num_disks} -f {-o ownername \| -s unowned \| -s sysid} disk1 [disk2] [...] are the names of the spare disks whose ownership assignment you want to modify. `-n` num_disks specifies a number of disks, rather than a series of disk names, to assign ownership to. `-f` forces the assignment of disks that have already been assigned ownership. `-o` ownername specifies the host name of the storage system head to which you want to reassign the disks in question. `-s unowned` modifies the ownership assignment of the disks in question back to "Not Owned." `-s` sysid is the factory-assigned NVRAM number of the storage system head to which you want to reassign the disks. It is displayed with the `sysconfig` command. Example The following command unassigns four disks on the FAS270c from the storage system sh1: sh1> `disk assign 0b.30 0b.29 0b.28 0b.27 -s 003303542 unowned`
3	Use the `disk show -v` command to verify the disk assignment modifications that you have just made.

Step

Action

View the spare disks whose ownership can safely be changed by entering the following command:

aggr status -r

Use the following command to modify assignment of the spare disks.

disk assign {disk1 [disk2] [...]|-n num_disks} -f 

{-o ownername | -s unowned | -s sysid}

disk1 [disk2] [...] are the names of the spare disks whose ownership assignment you want to modify.

-n num_disks specifies a number of disks, rather than a series of disk names, to assign ownership to.

-f forces the assignment of disks that have already been assigned ownership.

-o ownername specifies the host name of the storage system head to which you want to reassign the disks in question.

-s unowned modifies the ownership assignment of the disks in question back to "Not Owned."

-s sysid is the factory-assigned NVRAM number of the storage system head to which you want to reassign the disks. It is displayed with the sysconfig command.

Example

The following command unassigns four disks on the FAS270c from the storage system sh1:

sh1> disk assign 0b.30 0b.29 0b.28 0b.27 -s 003303542 
unowned

Use the disk show -v command to verify the disk assignment modifications that you have just made.

Re-using disks that are configured for software-based disk ownership

If you want to re-use disks from storage systems that have been configured for software-based disk ownership, you should take precautions if you reinstall these disks in storage systems that do not use software-based disk ownership.

Attention
Disks with unerased software-based ownership information that are installed in an unbooted storage system that does not use software-based disk ownership will cause that storage system to fail on reboot.

Take the following precautions, as appropriate:

Erase the software-based disk ownership information from a disk prior to removing it from its original storage system. See Erasing software-based disk ownership prior to removing a disk.
Transfer the disks to the target storage system while that storage system is in operation. See Automatically erasing disk ownership information.
If you accidentally cause a boot failure by installing software-assigned disks, undo this mishap by running the disk remove_ownership command in maintenance mode. See Undoing accidental conversion to software-based disk ownership.

Erasing software-based disk ownership prior to removing a disk

If possible, you should erase software-based disk ownership information on the target disks before removing them from their current storage system and prior to transferring them to another storage system.

To undo software-based disk ownership on a target disk prior to removing it, complete the following steps.

Step	Action
1	At the prompt of the storage system whose disks you want to transfer, enter the following command to list all the storage system disks and their RAID status. aggr status -r Note the names of the disks that you want to transfer. Note In most cases, (unless you plan to physically move an entire aggregate of disks to a new storage system) you should plan to transfer only disks listed as hot spare disks.
2	For each disk that you want to remove, enter the following command: disk remove_ownership disk_name disk_name is the name of the disk whose software-based ownership information you want to remove.
3	Enter the following command to confirm the removal of the disk ownership information from the specified disk. disk show -v Result The specified disk and any other disk that is labeled "not owned" is ready to be moved to other storage systems.
4	Remove the specified disk from its original storage system and install it into its target storage system.

Automatically erasing disk ownership information

If you physically transfer disks from a storage system that uses software-based disk ownership to a running storage system that does not, you can do so without using the disk remove_ownership command if that storage system is running Data ONTAP 6.5.1 or higher.

To automatically erase disk ownership information by physically transferring disks to a non-software-based storage system, complete the following steps.

Step	Action
1	Do not shut down the target storage system.
2	On the target storage system, enter the following command to confirm the version of Data ONTAP on the target storage system. version
3	If	Then
	The Data ONTAP version on the target storage system is 6.5.1 or later	Go to Step 4.
	The Data ONTAP version on the target storage system is earlier than 6.5.1	Do not continue this procedure; instead, erase the software-based disk ownership information on the source storage system, as described in Erasing software-based disk ownership prior to removing a disk.
4	Remove the disks from their original storage system and physically install them in the running target storage system. If Data ONTAP 6.5.1 or later is installed, the running target storage system automatically erases any existing software-based disk ownership information on the transferred disks.
5	On the target storage system, use the `aggr status -r` command to verify that the disks you have added are successfully installed.

Undoing accidental conversion to software-based disk ownership

If you transfer disks from a storage system configured for software-based disk ownership (such as the FAS270 storage system, or a cluster enabled for SnapMover vFiler^TM migration) to another storage system that does not use software-based disk ownership, you might accidentally mis-configure that target storage system as a result of the following circumstances.

You neglect to remove software-based disk ownership information from the target disks before you remove them from their original storage system.
You add the disks to a target storage system that does not use software-based disk ownership while the target storage system is off.
The target storage system is upgraded to Data ONTAP 6.5.1 or later.

Under these circumstances, if you reboot the target storage system in normal mode, the remaining disk ownership information causes the target storage system to convert to a mis-configured software-based disk ownership setup. It will fail to reboot.

To undo this accidental conversion to software-based disk ownership, complete the following steps.

Step	Action
1	Turn on or reboot the target storage system. When prompted to do so, press Ctrl-C to display the boot menu.
2	Enter the choice for booting in maintenance mode.
3	In maintenance mode, enter the following command: disk remove_ownership all The software-based disk ownership information is erased from all disks that have them.
4	Halt the storage system to exit maintenance mode by entering the following command: halt
5	Reboot the target storage system. The storage system will reboot in normal mode with software-based disk ownership disabled.