The process of a LUN Migration has been available in Navisphere as of Flare Code or Release 16. The LUN Migration is a move of a LUN within a Array from one LUN to another LUN. The process can be very simple; it is a two step process. First you have to create a New LUN which is for the “Source LUN” to copy over and a block by block copy of a “Source LUN” to its new location “Destination LUN”. After the copy is complete, it then moves the “Source” LUNs location to its new place in the Clariion.

With this feature, it will solves both capacity and performance provisioning at the same time –Move data to larger volume, different types of disks, different RAID levels, etc. Basically, this will help to solve both capacity and performance problems–Optimize performance up or down. Moves data within a CLARiiON CX system without application disruption–New LUN assumes the identity of the source LUN Tools.

 

Migration Process

1.     Create a Destination LUN

2.     Start a migration from the Source LUN

·         Select the destination LUN

·         “Start” the Migration Process – Copying block for block from Source LUN to Destination LUN

3.     Migration Completes

·         The Source LUN moves to the new location (Destination LUN)

·         The original Source LUN space becomes FREE space

 

Migration Rules:

The Destination LUN can be:

·         Equal to in size or larger

·         The same / different drive type

·         The same / different raid type

·         Regular LUN or MetaLUN

 

The Destination LUN cannot be:

·         Smaller in size

·         A SnapView, MirrorView, or SANCopy LUN

·         In a Storage Group

clariion lun migration
The Process of the Migration.
Again, this type of LUN Migration is an internal move of a LUN. In the illustration above, we are showing that we are moving Exchange off of the Vault drives onto Raid Group on another Enclosure in the Clariion.


1. Create a Destination LUN. This is going to be the Source LUN’s new location in the Clariion on the disks. The Destination LUN is a LUN which can be on a different Raid Group, on a different BUS, on a different Enclosure. The reason for a LUN Migration might be an instance where we may want to offload a LUN from a busy Raid Group for performance issues. Or, we want to move a LUN from Fibre Drives to ATA Drives. This we will discuss in the RULES portion.


2. Start the Migration from the Source LUN. From the LUN in Navisphere, we simply right-click and select Migrate. Navisphere gives us a window that displays the current information about the Source LUN, and a selection window of the Destination LUN. Once we select the Destination LUN and click Apply, the migration begins. The migration process is actually a two step process. It is a copy first, then a move. Once the migration begins, it is a block for block copy from the Source LUN (Original Location) to the Destination LUN (New Location). This is important to know because the Source LUN does not have to be offline while this process is running. The host will continue to read and write to the Source LUN, which will write to Cache, then Cache writing out to the disk. Because it is a copy, any new write to the source LUN will also write to the Destination LUN. At any time during this process, you may cancel the Migration if the wrong LUN was selected, or to wait until a later time. A priority level is also available to speed up or slow down the process.


3. Migration Completes. When the migration completes, the Source LUN will then MOVE to its new location in the Clariion. Again, this is transparent to the host, as it is still the same LUN as it was to begin with, just in a new space on the Clariion. The host doesn’t even know that the LUN is on a Clariion. It thinks the LUN is a local disk. The Destination LUN ID that you give a LUN when creating, will disappear. To the Clariion, that LUN never existed. The Source LUN will occupy the space of the Destination LUN, taking with it the same LUN ID, SP Ownership, and host connectivity. The only things that may or may not change based on your selection of the Destination might be the Raid type, Raid Group, size of the LUN, or Drive Type. The original space that the Source LUN once occupied is going to show as FREE Space in Navisphere on the Clariion. If you were to look at the Raid Group where the Source LUN used to live, under the Partitions tab, you will see the space the original LUN occupied as a Free. The Source LUN is still in the same Storage Group, assigned to the Host as it was before.

Migration Rules

The Destination LUN can be:
1. Equal to in size or larger. You can migrate a LUN to a LUN that is the exact same block count size, or to a LUN that is larger in size, so long as the host has the ability to see the additional space once the migration has completed. Windows would need a rescan, reboot of the disks to see the additional space, then using DISKPART, extend the Volume on the host. A host that doesn’t haven’t the ability to extend a volume, would need a Volume Manager software to grow a file system, etc.

2. The same or a different drive type. A destination LUN can be on the same type of drives as the source, or a different type of drive. For instance, you can migrate a LUN from Fibre Drives to ATA Drives when the Source LUN no longer needs the faster type drives. This is a LUN to LUN copy/move; so again, disk types will not stop a migration from happening, although it may slow the process from completing.


3. The same or a different raid type. Again, because it is a LUN to LUN copy, raid types don’t matter. You can move a LUN from Raid 1_0 to Raid 5 and reclaim some of the space on the Raid 1_0 disks. Or find that Raid 1_0 better suits your needs for performance and redundancy than Raid 5.


4. A Regular LUN or MetaLUN. The destination LUN only has to be equal in size, so whether it is a regular LUN on a 5 disk Raid 5 group or a Striped MetaLUN spread across multiple enclosures, buses, raid groups for performance is completely up to you.


However, the Destination LUN cannot be:
1. Smaller in size. The Destination LUN must be larger or equal and there is no way on a Clariion to shrink a LUN to allow a user to reclaim space that is not being used.


2. If the LUN are SnapView, MirrorView, or SanCopy LUN and being used by the Clariion to replicate data for local recoveries, replicate data to another Clariion for Disaster Recovery, or to move the data to/from another storage device, they are not available as a Destination LUN and cannot be migrate.


3. In the Storage Group. If a LUN is in Storage Group, the system will not along this to process as it belong to a Host. Therefore, the Clariion storage will not let you write over a LUN that potentially belongs to another host.

 

Explained:

To create a partition by using Diskpart in Windows System

1.     At a command prompt, type: Diskpart.exe

2.     At the DISKPART prompt, type: LIST DISK (Lists disks found. Make note of the drive number you wish to manipulate.)

3.     At the DISKPART prompt, type: Select Disk 1 (This selects the disk; make sure to type in the disk number from step 2.)

4.     At the DISKPART prompt, type: CREATE PARTITION PRIMARY ALIGN=1024
(Change the word PRIMARY to EXTENDED to create an extended partition.) (If you do not set a size (in MB), such as the above example for 10 GB, then all available space on the disk will be used for the partition.) (Seriously consider adding the following option to the end of the above command if you are using RAID (especially RAID 5) to improve disk I/O performance: ALIGN=64)

5.     At the DISKPART prompt, type: ASSIGN LETTER=D (Choose a drive letter not already being used.)

6.     At the DISKPART prompt, type: Exit

7.     Use the Command Prompt format command, Disk Administrator or any disk format utility to format the drive (typically using NTFS, of course).

 

Extend a partition in Windows with DISKPART. When it comes to adding space to a partition or volume, this method is superior to configuring Dynamic Disks. Dynamic Disk extensions only concatenate the newly added space, meaning they merely add the disk space to the "end" of the original partition without restriping the data.