Managing Spare Drives - NEC Express 5800 Series User Manual

controller slot=1 show ssdinfo
controller all show ssdinfo
controller all show ssdinfo detail
controller all show ssdinfo summary
SmartCache in SSACLI
This command is not supported.
SSD Smart Path
This command is not supported.
Rapid Parity Initialization methods
RAID levels that use parity (RAID 5, RAID 6 (ADG), RAID 50, and RAID 60) require that the parity blocks be
initialized to valid values. Valid parity data is required to enable enhanced data protection through
background surface scan analysis and higher performance write operations. Two initialization methods are
available:

Default – Initializes parity blocks in the background while the logical drive is available for access by the
operating system. A lower RAID level results in faster parity initialization.

Rapid – Overwrites both the data and parity blocks in the foreground. The logical drive remains invisible
and unavailable to the operating system until the parity initialization process completes. All parity
groups are initialized in parallel, but initialization is faster for single parity groups (RAID 5 and RAID 6).
RAID level does not affect system performance during rapid initialization.
Rapid Parity Initialization is available only for supported controllers and in arrays composed of supported
physical drives.
Example: of creating a logical drive with Rapid Parity Initialization:
=> ctrl slot=3 create type=ld drives=1e:1:1-1e:1:4 parityinitializationmethod=rapid
SSD Over Provisioning Optimization
Access to solid state devices can be optimized by deallocating all used blocks before any data is written to
the drive. The optimization process is performed when the first logical drive in an array is created, and when
a physical drive is used to replace a failed drive. Not all controllers support this option.
This feature is disabled by default in the CLI.
When creating the first logical drive in an array, the ssdoverprovisioningoptimization parameter specifies to
initialize solid state drives supporting the rapid parity initialization feature. The only valid option is "on".
Example:
ctrl slot=1 create type=ld drives=1I:1:1 ssdoverprovisioningoptimization=on
ctrl slot=1 create type=ld drives=1I:1:2 ssdopo=on

Managing spare drives

Assigning one or more online spare drives to an array enables you to postpone replacement of faulty drives.
However, it does not increase the fault-tolerance level of any logical drives in the array. For example, a logical
drive in a RAID 5 configuration suffers irretrievable data loss if two of its physical drives are simultaneously in
a failed state, regardless of the number of spare drives assigned to the array.
Any drive that you want to use as a spare must meet the following criteria:

It must be an unassigned drive or a spare for another array.

It must be of the same type as existing drives in the array (for example, SATA or SAS).

It must have a capacity no less than that of the smallest drive in the array.
SSA CLI 52