Dell PowerVault MD 32XX/36XX Series Storage Arrays CLI Guide

Create SSD Cache

Description

This command creates a read cache for a storage array using Solid State Disks (SSDs). Using high performance SSDs to cache read data improves the application I/O performance and response times, and delivers sustained performance improvement across different workloads, especially for high-IOP workloads. SSD cache maximizes the use of expensive fast SSDs.

SSD cache works in addition to the primary cache in the RAID controller module DRAM. With RAID controller module cache, the data is stored in DRAM after a host read. With SSD cache, the data is copied from user specified base virtual disks, and then cached on SSDs.

Syntax

create ssdCache userLabel="
                                 ssdCacheName"
                                 physicalDisks=(
                                 enclosureID1,drawerID1,slotID1 ... enclosureIDn,drawerIDn,slotIDn)
                                 [updateExistingVirtualDisks=(TRUE|FALSE)]
                                 [securityType=(none|capable|enabled)]

Parameters

Parameter	Description
`userLabel`	The alphanumeric identifier (including - and _) that you want to name the new SSD cache. Enclose the identifier in double quotation marks (" "). You can use any combination of alphanumeric characters, underscore (_), hyphen (-), and pound (#) for the identifier. Identifiers can have a maximum of 30 characters.
`physicalDisks`	The physical disks that you want to use to create the SSD cache. For dense expansion enclosures, specify the enclosure ID value, the drawer ID value, and the slot ID value for each physical disk that you want to assign to the SSD cache. For non-dense expansion enclosures, specify the enclosure ID value and the slot ID value for each physical disk that you assign to the SSD cache. Enclosure ID values are `0` to `99`. Drawer ID values are `0` to `4`. Slot ID values are `0` to `31`. Enclose the enclosure ID values, the drawer ID values, and the slot ID values in parentheses.
`updateExistingVirtualDisks`	This optional parameter specifies whether the SSD cache should be enabled for all existing virtual disks in the storage array. To enable the SSD cache for all existing virtual disks, set this parameter to `TRUE`. If you want to enable the SSD cache for individual virtual disks later, set this parameter to `FALSE`. The default value is `TRUE`.

The type of secure drives to use in the disk group. These settings are valid:

fips — To use FIPS compliant drives only.
sed — To use SED compliant drives only.

NOTE: At this time, the controller firmware does not support mixed FIPS and SED drives within disk groups and disk pools.

CAUTION: Use this parameter along with the securityType parameter. If you specify none for the securityType parameter, the value of the securePhysicalDisks parameter is ignored because non-secure disk groups do not need to have secure drive types specified.

Notes

A storage array can have only one SSD cache.

Only virtual disks created using hard disk physical disks can use the SSD cache. You cannot enable SSD cache on snapshot (legacy) virtual disks or snapshot images.

If all of the SSDs in the SSD cache are data assurance (DA)-capable and the DA premium feature is enabled, DA is automatically enabled for the SSD cache and cannot be disabled. In addition, you cannot add non-DA capable SSDs to a DA-enabled SSD cache.

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