A storage area network (SAN) is a network designed to attach computer storage devices such as disk array controllers and tape libraries to servers.
A SAN allows a machine to connect to remote targets such as disks and tape drives on a network for block level I/O. From the point of view of the class drivers and application software, the devices appear as locally attached devices.
There Are 2 Major Types Of SANs - Fibre Channel And iSCSI
They are similar in:
- Separation of storage resources from computing resources
- Transmit SCSI commands over the network
- Storage appears to be local SCSI disk to the host
- Allow advanced features such as snapshots, replication MPIO etc
- Scale bandwidth and through-put between servers and storage
- Support boot from SAN operations
- Require link level encryption for data movement over insecure links
Operationally FC and iSCSI are very different:
- FC uses fibre channel network infrastructure.
- iSCSI uses TCP/IP and ethernet infrastructure.
- FC has few targets with many LUNS. Target LUN pair is the network unit of routing.
- iSCSI has many targets with few LUNS. Unit of routing is TCP/IP connection.
- FC requires host bus adapters (HBA's) and FC switches
- iSCSI works with built in ethernet (initiators) orHBA'S and ethernet switches.
- FC security is managed via network configuration using zoning and masking at the switch and the storage device.
- iSCSI security is managed by the end points. The network is simply the transport; security is built into the standard.
- FC speeds are 1gb, 2gb and 4gb.
- iSCSI ethernet speeds are 100mb, 1gb, 10gb.
SAN Solutions
- Dell Equallogic PS-Series iSCSI SAN
- Lefthand Networks SAN IQ
Fibre Channel SAN Solutions
- Digidata T-3000 Series SAN
- Hitachi (HDS) Tagmastore
- Overland Ultamus 1200
