Check to see if the windows servers have any hidden devices that may be causing issues. Several events can occur that contribute to the addition of ghost devices in the Windows 2000 Device Manager. Some of these include adding or removing hardware, changes to tape drives or tape libraries, or failure to use persistent binding, static indexing, or hard AL_Pa's on storage area network (SAN) equipment which
can allow changes to SCSI device path presentation of a device to the operating system. These ghost devices can retain Port, SCSI, Target, and logical unit number (LUN) information and conflict with the active devices being used by Windows 2000. Under these circumstances, hardware instability can result as well as other undesirable device operations.
Running the device discovery wizard, for example, may list 20 tape drives when only 10 tape drives physically exist. This information is being pulled from the operating system and can incorrectly associate tape device information with the VERITAS NetBackup (tm) hardware configuration.
You may also experience tape device drivers "disappear" or roll back to the previous drivers after a NetBackup tape device driver update. In this scenario, the drivers were actually applied to the ghost device and upon reboot, the active devices loaded the previous driver information.