sybase全库备份时出IOCTL call failed 错

今天在sybase数据库全备时出现错误，
sybase12.5 for aix
Jul  5 10:46:08 2008: Backup Server: 4.141.2.30: [11] The 'ioctl' call failed for device '/dev/rmt0.1' with error number 5 (I/O error). Refer to your operating system documentation for further details.
Jul  5 10:46:08 2008: Backup Server: 4.20.2.1: Device '/dev/rmt0.1': I/O error, write of tape mark failed.
Jul  5 10:46:14 2008: Backup Server: 4.55.2.1: Device validation error: couldn't open raw device /dev/rmt0.1,error: Device not ready
Jul  5 10:46:20 2008: Backup Server: 4.55.2.1: Device validation error: couldn't open raw device /de
v/rmt0.1, error: Device not ready
Jul  5 10:46:26 2008: Backup Server: 4.55.2.1: Device validation error: couldn't open raw device /de
v/rmt0.1, error: Device not ready
请高手帮助。