Storage
Storage is a broad term for the fundamental technologies we use to store our information. This concept includes storage media, the disk subsystem with all its functions, and the networks used for sharing and consolidating the storage infrastructure.
Storage media: the hard disk has dominated over the last few decades and will continue to be our most common storage medium. These are available in two basic forms: capacity-optimised for a low price per GB (SATA), and performance-optimised for read/write performance (FC, SAS). The use of memory modules presented in hard disk form – also referred to as solid state disk – are starting to be used for the most I/O-intensive applications.
Disk subsystem: This has developed over the years, from a simple disk box to various RAID levels to solutions which use advanced controller functions. These advanced functions include snapshots, cloning, replication, thin provisioning, deduplication and virtualisation of heterogeneous storage systems.
Storage networks: sharing resources over a network is a powerful tool for consolidating storage infrastructure. There are a number of different protocols available over the two basic networks, Fibre Channel and Ethernet; the most common ones are listed below.
Over Ethernet we have the file sharing protocols NFS and CIFS, as well as block-based protocols such as iSCSI, FCIP and FCOE.
The block-based protocols SCSI and FCP are run over Fibre Channel.