Drives
Depending on your model, the system supports flash drives, enterprise, and nearline class drives. For SAN Volume Controller 2145-CG8 or 2145-CF8 models, the system supports flash drives only. For SAN Volume Controller 2145-SV1 and SAN Volume Controller 2145-DH8, the system supports flash drives, enterprise, and nearline class drives. A drive object represents the physical drive. The system creates this object automatically when a supported drive is detected and a drive ID is assigned.
For SAN Volume Controller 2145-CG8 or 2145-CF8 nodes, one or more pairs of nodes can contain 0 - 4 drives per node. SAN Volume Controller 2145-SV1 and SAN Volume Controller 2145-DH8 nodes support two chains that each contain 10 expansion enclosures. Each I/O group can contain up to 20 expansion enclosures. Each expansion enclosure is attached to each node in the I/O group. Drives are installed in the drive slots in the front of the node or enclosure. Redundancy and high availability of data is provided through volume mirroring and different array configurations.
- 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.
- 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 are disk drives that are optimized for performance.
- 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 Unused. The Use attribute, which is specified on the chdrive command, determines if the drive can be formed into an array.