A device may have hardware problems or a device path may have been changed and the TSM server cannot find the new path with the SAN Discovery option set to ON. The TSM server cannot get device information when it cannot open the device. Therefore, the TSM server cannot validate the drive serial number to see if this drive with the failed open operation is the same drive as it previously used. The causes of this failed open device may be a bad cable, a bad drive or a bad HBA card. However, if an incorrect drive is used (for example, an incorrect device path) and with the SAN discovery option set to OFF or UNSCANNEDPATHOFF, the TSM server will not search the SAN environment to get a proper device.
The TSM server may mark this device offline for SAN Discovery option ON or UNSCANNEDPATHOFF.
Users should check the TSM server option file first. If SAN discovery option is set to OFF or UNSCANNEDPATHOFF, set it to ON and check for hardware errors on the device. If the SAN discovery option is set to ON, then check the device to see if there is a hardware problem.