ETERNUS SF Storage Cruiser V16.5 Operation Guide for Optimization Function

3.5.4 Change Number of Layers of Tier Pool

By changing from the Tier pool of one layer to the Tier pool of two or three layers, the Automated Storage Tiering can be operated.

Moreover, the Tier pool of two layers can be changed to the Tier pool of three layers.

Point

• As for the sub-pool of one layer, the layer level is set to High (fixation) beforehand.

• As for the sub-pool of two layers, the layer level becomes set of Low and High (fixation).

• The number of layers of the Tier pool in which RAID groups are being deleted cannot be changed.

The procedures to change the layer number and begin the Automated Storage Tiering are as follows:

1. Stop the Automated Storage Tiering for the target Tier pool.
   Refer to "Start/Stop Automated Storage Tiering for Tier Pool" in the ETERNUS SF Web Console Guide for the operational procedure.

2. Create a Tiering policy.
   Refer to "Create Tiering Policy" in the ETERNUS SF Web Console Guide for the creating method.
   If use the Tiering policy that has already been created, this step is unnecessary.

3. Change the layer number of the target Tier pool.
   The items which can be specified when changing the number of layers of the Tier Pool are as follows.

   Item Name	Specification (*1)	Explanation
   Policy Name	Optional	Specify the Tiering policy to associate with the Tier pool. Make a selection from the Tiering policies that have been defined and are displayed in the pull-down list. The Tiering policies that cannot be applied to the Tier pool configuration after the change are not displayed.
   Assigned CM	Optional	Only when a CM in charge has been specified at the time of the Tier pool creation, the CM in charge can be added. As needed, specify the CM which takes charge of the Tier pool being created. The checkbox is not checked by default (a CM in charge is not specified). To specify a CM which takes charge of the Tier pool, check the checkbox. All of the CMs present on the storage device are displayed, make a selection from these.
   Number of Layers	Required	Specify the number of layers of the Tier pool. Only increasing the number of layers is possible. Add a Low sub-pool when changing from one layer to two layers. Add two sub-pools in order of the Low sub-pool and the Middle sub-pool when changing from one layer to three layers. Add the Middle sub-pool when changing from two layers to three layers.
   Disk Selection	Required	Specify the method for the selection of disks that configure the sub-pool. The default setting is "Auto" (automatic selection). When "Auto" is selected, in the screen to configure the Low sub-pool and Middle sub-pool, it is necessary to specify a minimum required capacity for each of the sub-pools. When "Manual" is selected, in the screen to configure the Low sub-pool and Middle sub-pool, it is necessary to specify the disks that configure each of the sub-pools.

   *1: When a specification is omitted for the item of which specification is "Optional", a default value is configured.

   Refer to "Change Number of Layers of Tier Pool" in the ETERNUS SF Web Console Guide for the operational procedure.

4. Change the layer level of each layer and the sub-pool name, and set the corresponding Tiering policy if necessary.
   Refer to "Change Tier Pool" in the ETERNUS SF Web Console Guide for the operational procedure.

5. Start the Automated Storage Tiering for the target Tier pool.
   Refer to "Start/Stop Automated Storage Tiering for Tier Pool" in the ETERNUS SF Web Console Guide for the operational procedure.