哪位高手帮我诊断下

新加了一块scsi硬盘，做为论坛附件用，并将其mount到attachments。

这样运行一个月正常，最近升级了正式斑discuz，运行良好。

但前天发现附件无法上传，后来检查发现attachments没有内容了(attachments mount到第二个新安装的硬盘)并发现以下日志：
Oct  6 23:53:33 www kernel: aacraid:ID(0:03:0); Error Event [command:0x28]
Oct  6 23:53:33 www kernel: aacraid:ID(0:03:0); Medium Error [k:0x3,c:0x11,q:0x0]
Oct  6 23:53:33 www kernel: aacraid:ID(0:03:0); Unrecovered Read Error
Oct  6 23:53:35 www kernel: aacraidrive 0:3:0 returning error
Oct  6 23:53:35 www kernel: aacraid:Container 1 returning error on drive 0:3:0
Oct  6 23:53:35 www kernel: aacraid:Container 1 Returned Error to Adapter Cache
Oct  6 23:53:35 www kernel: read_callback: read failed, status = 5
Oct  6 23:53:35 www kernel: SCSI disk error : host 0 channel 0 id 1 lun 0 return code = 8000002
Oct  6 23:53:35 www kernel: Info fld=0x0, Current sd08:11: sense key Hardware Error
Oct  6 23:53:35 www kernel: Additional sense indicates Internal target failure
Oct  6 23:53:35 www kernel:  I/O error: dev 08:11, sector 13683704
Oct  6 23:53:35 www kernel: read_callback: read failed, status = 5
Oct  6 23:53:35 www kernel: SCSI disk error : host 0 channel 0 id 1 lun 0 return code = 8000002
Oct  6 23:53:35 www kernel: Info fld=0x0, Current sd08:11: sense key Hardware Error
Oct  6 23:53:35 www kernel: Additional sense indicates Internal target failure
Oct  6 23:53:35 www kernel:  I/O error: dev 08:11, sector 13683712
Oct  6 23:53:35 www kernel: read_callback: read failed, status = 5
Oct  6 23:53:35 www kernel: SCSI disk error : host 0 channel 0 id 1 lun 0 return code = 8000002
Oct  6 23:53:35 www kernel: Info fld=0x0, Current sd08:11: sense key Hardware Error
Oct  6 23:53:35 www kernel: Additional sense indicates Internal target failure
Oct  6 23:53:35 www kernel:  I/O error: dev 08:11, sector 13683704
Oct  6 23:53:35 www kernel: read_callback: read failed, status = 5
Oct  6 23:53:35 www kernel: SCSI disk error : host 0 channel 0 id 1 lun 0 return code = 8000002
Oct  6 23:53:35 www kernel: Info fld=0x0, Current sd08:11: sense key Hardware Error
Oct  6 23:53:35 www kernel: Additional sense indicates Internal target failure

于是重新启动机器，附件可以上传了，attachments也有内容。但昨天又发现同样的问题，重新启动恢复正常。但晚上又发生同样的问题，重新启动就不正常了。开不了机器，显示：
give root password for维护(按ctr-D继续)

请帮我诊断下是什么原因。