Dell TL2000 manual Cables and Speeds, Using Zoning to Isolate Devices and Enhance Security

vLN Port: (default setting) - an automatic configuration that tries arbitrated loop first, then switched fabric

vL Port - arbitrated loop

vN Port - point to point protocol in a switched fabric topology

Cables and Speeds

Ultrium 3 and Ultrium 4 Fibre Channel tape drives use LC duplex fiber optics cables.

The maximum distances that the library supports on a Fibre Channel link is determined by the link speed, the type of fiber (50-micron or 62.5-micron), and the device to which the library is attached.

If the library attaches to an HBA (Host Bus Adapter), refer to the distances that are supported by the HBA. If the library attaches to a switch, the supported distances are:

vFor a 50-micron cable:

–1-Gbit link speed = up to 500 m (1640 ft)

–2-Gbit link speed = up to 300 m (984 ft)

–4-Gbit link speed = up to 150 m (492 ft)

vFor a 62.5-micron cable:

–1-Gbit link speed = up to 175 m (574 ft)

–2-Gbit link speed = up to 150 m (492 ft)

–4-Gbit link speed = up to 70 m (230 ft)

The library uses 50-micron cables internally. Therefore, you must use a 50-micron cable to attach to the library’s port. To attach to a 62.5-micron SAN, you must attach the 50-micron cable to an active port, such as a port on a switch.

Using Zoning to Isolate Devices and Enhance Security

For security reasons, it is important to limit the devices that a server or servers can recognize or access. Also, some performance configurations and SAN configurations can result in a device being seen multiple times from the same server. For example, if you have two HBAs from the same server connected to an Ultrium Tape Drive in the library, the drive will be detected and appear as two logical devices. That is, there will be two special files for one physical device. Zoning can address these issues.

Zoning allows you to partition your SAN into logical groupings of devices so that each group is isolated from the other and can only access the devices in its own group. Two types of zoning exist: hardware zoning and software zoning. Hardware zoning is based on physical fabric port number. Software zoning is defined with a World Wide Node Name (WWNN) or World Wide Port Name (WWPN). While zoning can be reconfigured without causing an outage, some zoning configurations can become complicated. The advantage of the library’s WWNN implementation is that you can avoid the exposure of introducing zoning errors because you do not have to change the zoning configuration if a drive needs service or replacement.

Sharing on a Storage Area Network

With Storage Area Network (SAN) components, the possibilities for connecting multiple systems and multiple drives have increased. Not all software and systems are designed to share drives. Before you install a drive that would allow two systems to share it, check that the systems and their software support sharing. If your software does not support sharing, note that Fibre Channel switches have a

Chapter 3. Installation Planning 3-9