Spectra Logic Spectra 12000 manual TAOS User Interfaces, Sharing Tape Devices

Chapter 7. Configuring the Spectra 12000 E-QIP 67

Sharing Tape Devices

TAOS ITP and TAOS NDMP both allow a set of tape resources to be shared between multiple hosts. Care must be taken to ensure that multiple requests are not being sent to same tape drive at the same time.

With TAOS NDMP, there is typically a backup application server that manages access to the tape drives. Even though multiple NAS devices can access the tape device directly these requests are routed through a single backup server. This server, then, is responsible for managing access to the drives. As long as the devices and NAS clients are configured properly in the software, resource contention is eliminated. Access to TAOS NDMP functionality is also password protected--any NAS host wishing to write to the Spectra 12000 library must authenticate themselves with the correct username and password. This is also generally set up in the backup software.

With TAOS ITP, there may be many backup applications on many hosts, all responsible for managing their own access to the tape drives, and as the E-QIP looks like a locally attached resource to each configured host, each host has no idea that other hosts also have access. There are three ways to manage resource contention with TAOS ITP. First, the E-QIP will only be visible to hosts where the TAOS ITP driver has been installed.

Second, the TAOS ITP configuration utilities in the E-QIP allow you to configure IP address ranges of hosts that can access the library. Finally, devices can be locked during use by going through one of the available configuration interfaces. When a device has been locked, no other host can gain access to the drive until it is unlocked.

In any case, if multiple hosts will be accessing the library, some access management scheme must be implemented to prevent stored data written by one host from being overwritten by another.

TAOS User Interfaces

There are two user interfaces available to access and change TAOS options: a serial port interface and a TAOS ITP control panel (available on Windows systems only). The serial interface is the only way to set the Ethernet configuration of the library, however, once the Ethernet parameters have been set and the unit is connected to your network, the TAOS ITP control panel can be used to view settings.