To dynamically accelerate system performance, you can
use the SSD Cache feature to cache the most frequently accessed data
("hot" data) onto lower latency Solid State Drives (SSDs). SSD Cache
is used exclusively for host reads.
Before
you begin
Your storage array must contain some SSD drives.
About
this task
When you create SSD Cache, you can use a single
drive or multiple drives. Because the read cache is in the storage
array, caching is shared across all applications using the storage
array. You select the volumes that you want to cache, and then caching
is automatic and dynamic.
Follow these guidelines when you create
SSD Cache.
- You can enable security
on the SSD Cache only when you are creating it, not later.
- Only one SSD Cache is supported per storage array.
- The maximum usable SSD Cache capacity on a storage
array is dependent on the controller’s primary cache capacity.
- SSD Cache is not supported on snapshot images.
- If you import or export volumes that are SSD Cache
enabled or disabled, the cached data is not imported or exported.
- Any volume assigned to
use a controller's SSD Cache is not eligible for an automatic load
balance transfer.
- If the associated volumes
are secure-enabled, create a secure-enabled SSD Cache.
- Select .
- Click .
The Create SSD Cache dialog box appears.
- Type a name
for the SSD Cache.
- Select the SSD
Cache candidate that you want to use based on the following characteristics.
| Characteristic |
Use |
| Capacity |
Shows the available capacity in GiB. Select
the capacity for your application’s storage needs.
The maximum
capacity for SSD Cache depends on the controller’s primary cache capacity.
If you allocate more than the maximum amount to SSD Cache, then any
extra capacity is unusable.
SSD Cache capacity counts towards
your overall allocated capacity.
|
| Total drives |
Shows the number of drives available for this
SSD cache. Select the SSD candidate with the number of drives that
you want. |
| Secure-capable |
Indicates whether the SSD Cache candidate
is comprised entirely of secure-capable drives, which can be either
Full Disk Encryption (FDE) drives or Federal Information Processing
Standard (FIPS) drives.
If you want to create a secure-enabled
SSD Cache, look for Yes - FDE or Yes - FIPS in the Secure-capable
column.
|
| Enable security? |
Provides the option for enabling the Drive
Security feature with secure-capable drives. If you want to create
a secure-enabled SSD Cache, select the Enable Security check box.
Note: Once enabled, security cannot be disabled. You can enable security
on the SSD Cache only when you are creating it, not later.
|
| DA capable |
Indicates if Data Assurance (DA) is available
for this SSD Cache candidate. Data Assurance (DA) checks for and corrects
errors that might occur as data is transferred through the controllers
down to the drives.
If you want to use DA, select an SSD Cache
candidate that is DA capable. This option is available only when the
DA feature has been enabled.
SSD Cache can contain both DA-capable
and non-DA-capable drives, but all drives must be DA-capable
for you to use DA.
|
- Associate the
SSD Cache with the volumes for which you want to implement SSD read
caching. To enable SSD Cache on compatible volumes immediately, select
the Enable SSD Cache on existing compatible volumes that
are mapped to hosts check box.
Volumes are compatible if they share the same Drive Security
and DA capabilities.
- Click Create.