System::Disk¶

Introduced : BIG-IP_v10.1.0

The Disk interface enables you to manage the disks in the system. The disk objects come in two flavors. “Physical disks” are the actual hardware disk drives, which can be anything from a true hard disk to a compact flash drive to a USB flash drive. Physical disks are addressed by their serial numbers. “Logical disks” are the view of the disk drives from the system&aposs point of view, abstracting the disk itself, making all disk drives look the same whether they are a true hard disk, a flash drive, or a full disk array. In other words, a logical disk can hold one or more physical disks. Logical disks are addressed by the LogicalDisk identifier, which includes their logical name (e.g., “HD2”, “CF1”, “MD1”) and their chassis slot identifier. It is important to note the potentially confusing relationship between logical and physical disks and their identifiers. All physical disks can be addressed by a LogicalDisk identifier, though it is not guaranteed that all physical disks have an entry in the logical disk table. The logical disk identifier for a physical disk is dependent on the connection of the disk drive to the system, so can change if the system&aposs disk drive configuration changes. On the other hand, all logical disks hold one or more physical disks, which can have a direct one-to-one mapping for a single disk drive or a one-to-many mapping for a disk array. To avoid problems, physical disks should be ideally addressed only by their serial numbers and logical disks only by their LogicalDisk identifiers. Addressing physical disks by their LogicalDisk identifier is supported as a convenience for any user-generated input. Be careful with these distinctions as you use this interface. The application volume component provides better granularity for managing disks. A logical disk can be logically segmented into several application volumes. An application volume belongs to only one logical disk and can never be shared. The visibility of the application volume can be confined to a particular software volume set or it can be made global to make it visible across all control planes. Once set, the volume set visibility property cannot be modified. Application volumes are created during the provisioning of disk-using application modules (e.g., “DATASTOR”, “VCMP” etc.). The application volumes may be discarded by the software(e.g. during module provisioning) unless its preservability property is changed to precious.