Drives

The system supports a variety of different types of drives and drive classes. These drives are used to create arrays that provide capacity for pools and volumes.

A drive object represents the physical drive. The system creates this object automatically and assigns a drive ID when a supported drive is detected through the serial-attached SCSI (SAS) connections.

You can select to have the system to automatically assign all detected internal drives to pools, or select to customize the configuration. When the system automatically assigns drives, pools are created based on the available drive classes and recommended array configurations. In this case, the system might not use all available drives if they do not meet configuration recommendations. If you choose to customize, you can adjust the configuration based on the number of drives and drive criteria. These arrays are presented as MDisks, which can be added to pools.Depending on the model, you can either have one or more pairs of nodes with 0 - 4 drives per node. Other models support up to two expansion enclosures for each I/O group; each expansion enclosure is attached to each node in the I/O group.

If the MDisks are created from different tiers of storage, Easy Tier® can be used to automatically manage the migration of highly used data to faster drives.

The system supports the following tiers of drives:

Tier 0 flash: Tier 0 flash drives are high-performance flash drives that process read and write operations and provide faster access to data than enterprise or nearline drives. For most Tier 0 flash drives, as they are used the system monitors their wear level and issues warnings when the drive is nearing replacement.
Tier 1 flash: Tier 1 flash drives are lower-cost flash drives, typically with larger capacities, but slightly lower performance and write endurance characteristics. As these drives are used, the system monitors their wear level and issues warnings when the drive is nearing replacement.
Enterprise disks: Enterprise disks are disk drives that are optimized for performance.
Nearline disks: Nearline disks are disk drives that are optimized for capacity.

When a drive is moved between drive slots, the drive ID is maintained unless its Use property is changed to Unused. In the command line interface, the use parameter, which is specified on the chdrive command, determines if the drive can be formed into an array.

To access information about drives in the management GUI, select Monitoring > System. On the System - Overview page, click the directional arrow next the enclosure that contains the drives. On the Enclosure Details page, select Drive under Front View to highlight and display information on the drives. To display information about the drives in the command-line interface, use the lsdrive command.

Note: Do not replace a drive unless the drive fault LED is on or you are instructed to do so by a fix procedure.