NEC Express 5800 Series User Manual

Also see for Express 5800 Series: Maintenance Guide User guide User guide Installation guide

Contents

SSA CLI 52controller slot=1 show ssdinfocontroller all show ssdinfocontroller all show ssdinfo detailcontroller all show ssdinfo summarySmartCache in SSACLIThis command is not supported.SSD Smart PathThis command is not supported.Rapid Parity Initialization methodsRAID levels that use parity (RAID 5, RAID 6 (ADG), RAID 50, and RAID 60) require that the parity blocks beinitialized to valid values. Valid parity data is required to enable enhanced data protection throughbackground surface scan analysis and higher performance write operations. Two initialization methods areavailable: Default – Initializes parity blocks in the background while the logical drive is available for access by theoperating 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 invisibleand unavailable to the operating system until the parity initialization process completes. All paritygroups 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 supportedphysical 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=rapidSSD Over Provisioning OptimizationAccess to solid state devices can be optimized by deallocating all used blocks before any data is written tothe drive. The optimization process is performed when the first logical drive in an array is created, and whena 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 toinitialize 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=onctrl slot=1 create type=ld drives=1I:1:2 ssdopo=onManaging spare drivesAssigning 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 logicaldrive in a RAID 5 configuration suffers irretrievable data loss if two of its physical drives are simultaneously ina 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.