Setup Extreme Cache Pool

Overview

This function is used to perform the following settings for Extreme Cache Pool.

  • The Extreme Cache Pool setting (enabled or disabled)

  • The Extreme Cache Pool capacity setting

  • Tuning parameters

To use Extreme Cache Pools, 800GB SSDs must be installed in each of the CMs in the CE or DE are required.

Extreme Cache Pool stores data in the RAID group that is controlled by the CM.

Caution
  • The ETERNUS DX100 S5/DX200 S5 supports Extreme Cache Pools.
  • Extreme Cache Pool does not work when operating in an environment with a high cache hit rate.
  • Extreme Cache Pool cannot be enabled under the following conditions:
    • Pinned data exists in the storage system
    • A CM that is not in the "Normal" state exists
  • If an Extreme Cache Pool includes a RAID group without an "Available" state, the setting values and mode of the tuning parameter cannot be changed.
  • Value SSDs and FIPS-compliant Self Encrypting Drives cannot be used for Extreme Cache Pools.
Note
  • The Extreme Cache Pool setting (enabled or disabled), the memory size, and the tuning parameters can be changed during business operations.
  • The Extreme Cache Pool mode (enabled or disabled) of the storage system and the set states of Extreme Cache Pool for each volume are not linked. Regardless of the mode of the Extreme Cache Pool for the storage system, the default state of Extreme Cache Pool for each volume is "Enable".
  • Regardless of whether the Extreme Cache Pool is enabled (or disabled) for each volume, External Volumes do not use the Extreme Cache Pool.
  • The cache hit rate of Extreme Cache Pool for each volume can be checked in the [Performance Information] screen. Refer to the [Performance (Host I/O)] function or the [Performance (Advanced Copy)] function for details.
  • RAID groups that are used as Extreme Cache Pools are configured with RAID0 that has a single drive.
  • If multiple CMs are installed in the storage system, setting the same Extreme Cache Pool capacity for each CM is recommended.
  • Enabling or disabling Extreme Cache Pool for each volume can be performed. Refer to the [Modify Cache Parameters] function for details.
  • Extreme Cache Pool for the relevant volume can be used when the Extreme Cache Pool for the storage system and the Extreme Cache Pool for the volume are both enabled.
  • To stop using Extreme Cache Pools, release Extreme Cache Pool. Refer to the [Release Extreme Cache Pool] function for details.

User Privileges

Availability of Executions in the Default Role

Default role Availability of executions
Monitor  
Admin
StorageAdmin  
AccountAdmin  
SecurityAdmin  
Maintainer

Refer to "User Roles and Policies" for details on the policies and roles.

Display Contents

Settings (Extreme Cache Pool Settings)

Extreme Cache Pool Settings

Item Description Setting values
Mode Select whether to enable or disable the Extreme Cache Pool for the storage system.

Enable

Disable (Default)
Usage

The usage of the Extreme Cache Pool (Read-Only Cache) is displayed.

A "-" (hyphen) is displayed when the mode is "Disable".

  

Settings (Extreme Cache Pool Capacity Settings)

Extreme Cache Pool Capacity Settings

Item Description Setting values
CM

All the CMs in the storage system are displayed.

CM#x

x: CM number

  
Capacity

The Extreme Cache Pool capacity that is to be set to the relevant CM is displayed.

If the Extreme Cache Pool capacity is not specified, "0 GB" is displayed.

  
Encryption by CM

Select the encryption status of the Extreme Cache Pool area in the relevant CM.

  • On

    Create an Extreme Cache Pool area that is encrypted by CM.

  • Off

    Create an Extreme Cache Pool area that is not encrypted by CM.

To use an Extreme Cache Pool as secondary cache memory for encrypted volumes, select "On" for this item.

This mode is available only when the encryption mode is enabled.

Caution
  • If the Extreme Cache Pool areas are not encrypted even when encrypted volumes are included in the volumes that are controlled by the relevant CM, Extreme Cache Pools cannot be used as secondary cache memory for I/O to the encrypted volumes.
  • If the volumes controlled by the relevant CM are all unencrypted, encrypting the Extreme Cache Pool area is not required.
Note
  • If "SSD SED" is selected for drives that are used as Extreme Cache Pool areas, "On (SED)" is displayed for this item. This item is grayed out and then becomes unselectable.

On

Off (Default)
Member Drives

The location information of the drives that are used as Extreme Cache Pool areas to be set in the relevant CM is displayed. If no drives are selected, a "-" (hyphen) is displayed.

CE Slot#x

DE#yy Slot#x

x: Slot number

yy: DE number

  

Select Drives

Drives can be selected from the list or the installation image. To switch between the list and the installation image, click the tab.

Extreme Cache Pool Capacity Settings

Item Description
CM

All the CMs in the storage system are displayed.

CM#x

x: CM number
Capacity

The Extreme Cache Pool capacity that is to be set to the relevant CM is displayed.

If no drives are set, "0 GB" is displayed.

[Tabular] Tab

Click the [Tabular] tab to select drives from the list. Unused drives (SSDs or SSD SEDs) are displayed on the list.

Item Description
Checkbox to select drives

Select the same number of checkboxes as the number of CMs for the drives (800 GB SSDs) used in the RAID groups that configure the Extreme Cache Pools.

The initially selected drive is set as the Extreme Cache Pool area for CM#0.

The second selected drive is set as the Extreme Cache Pool area for CM#1.

The checkbox is selected for a drive that has already been selected as the Extreme Cache Pool area.

Caution
  • Note that CMs cannot be specified when selecting drives that are to be used as the Extreme Cache Pool areas.

Refer to "Drive Selection" ([Tabular] Tab) in the [Create RAID Group] function for display items.

[Graphic] Tab

Click the [Graphic] tab to select drives from the drive installation image. The installation images of all the drives installed in the storage system are displayed. Checkboxes are displayed for unused drives (SSDs or SSD SEDs).

Item Description Setting values
DE selection list box

Select the DE group.

DE groups are displayed as options in the list box when at least one CE or DE in the DE group is installed in the storage system.

DE#0x
Checkbox to select drives

Select the same number of checkboxes as the number of CMs for the drives (800 GB SSDs) used in the RAID groups that configure the Extreme Cache Pools.

The initially selected drive is set as the Extreme Cache Pool area for CM#0.

The second selected drive is set as the Extreme Cache Pool area for CM#1.

The checkbox is selected for a drive that has already been selected as the Extreme Cache Pool area.

Caution
  • Note that CMs cannot be specified when selecting drives that are to be used as the Extreme Cache Pool areas.
  

Refer to "Drive Selection" ([Graphic] Tab) in the [Create RAID Group] function for display items.

Settings (Tuning Parameter Settings)

Tuning Parameter Settings

Item Description Setting values

Initial Caching Threshold

Specify the threshold that affects how frequently data is stored in Extreme Cache Pool.

The greater the value is, the less frequently data is stored in Extreme Cache Pool. The smaller the value is, the more frequently data is stored in Extreme Cache Pool.

If the set value is exceeded, it is assumed that the relevant data is read frequently and the data is stored in Extreme Cache Pool.

This parameter specifies the threshold value that is used until the Extreme Cache Pool memory is full after Extreme Cache Pool is enabled.

Caution

  • This parameter is used for performance tuning. It is not necessary to change the default setting (1) for normal use.

1 (Default) -16

Caching Threshold

Similar to "Initial Caching Threshold", this parameter specifies the threshold that affects how frequently data is stored in Extreme Cache Pool.

If the set value is exceeded, it is assumed that the relevant data is read frequently and the data is stored in Extreme Cache Pool.

This threshold value is used after the Extreme Cache Pool memory is full.

Caution

  • This parameter is used for performance tuning. It is not necessary to change the default setting (5) for normal use.

  • This item is available only when the "Not relocate Cache Data" checkbox is cleared (cache data is relocated).

1 - 16

5 (Default)

"Not relocate Cache Data" checkbox

Select or clear the "Not relocate Cache Data" checkbox.

If the checkbox is selected, new data is not stored (relocated) after the Extreme Cache Pool memory is full.

If the checkbox is cleared, the storage system chronologically deletes the stored data from Extreme Cache Pool beginning with the oldest and stores (relocates) new data.

If the data is not relocated, select the checkbox

If the data is relocated, clear the checkbox (Default)

Caching Priority

Specify the concurrency of the staging process when data is stored in Extreme Cache Pool.

The greater the value is, the higher the concurrency is set for storing data in Extreme Cache Pool. The smaller the value is, the lower the concurrency is set for storing data in Extreme Cache Pool.

Caution

  • This parameter is used for performance tuning. It is not necessary to change the default value ("10 (Fastest)") for normal use.

10 (Fastest) (Default)

9

8

7

6

5

4

3

2

1

Monitoring I/O

Select the I/O type for storing data in Extreme Cache Pool.

Read (Default)

Read / Write

Operating Procedures

When Enabling Extreme Cache Pool

  1. Click [Setup Extreme Cache Pool] in [Action].

    Note
    • To change the tuning parameters only, proceed to Step 4. The [Set] button can be clicked even if "Mode" is "Enable".

  2. Select "Enable" for "Mode".

  3. Click the [Select Drives] button.

    Select SSDs from the list or the installation image to configure an Extreme Cache Pool as the number of CMs, and click the [OK] button.

    → Returns to the [Extreme Cache Pool Settings] screen.

    Caution
    • If the number of selected drives differs from the number of CMs, the [OK] button cannot be clicked.

  4. If required, specify the tuning parameters and then click the [Set] button.

    → A confirmation screen appears.

  5. Click the [OK] button.

    → The setting of Extreme Cache Pool starts.

  6. Click the [Done] button to return to the [Extreme Cache Pool] screen.

When Disabling the Extreme Cache Pool

Note
  • To disable the Extreme Cache Pool, set the Extreme Cache Pool capacity to "0 GB" in advance. Refer to the [Release Extreme Cache Pool] function for details.

  1. Click [Setup Extreme Cache Pool] in [Action].

  2. Select "Disable" for "Mode" and click the [Set] button.

    → A confirmation screen appears.

    Note
    • The tuning parameters remain even when the Extreme Cache Pool mode is changed from "Enable" to "Disable".

  3. Click the [OK] button.

    → The setting of Extreme Cache Pool starts.

  4. Click the [Done] button to return to the [Extreme Cache Pool] screen.