我试图确定这个错误rejecting I/O to offline device是什么，如本系统日志末尾所示。
想法：
- RAID-0 配置问题（我们在 RAID-0 中有 2 个 4TB 磁盘，我确实看到了有关它的警告）
- 虚拟 CD - 该服务器上没有 CD，但我确实通过 IPMI/KVM 工具附加了虚拟 CD 用于安装。虽然现在不应该附加它，但我看到了一些关于它的消息。
除了上述说明之外，这是 ubuntu 12.04 的新安装，是通过网络引导和 IPMI/KVM 控制台完成的。
Apr 12 19:42:46 ubuntu dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3
Apr 12 19:42:46 ubuntu dhclient: DHCPREQUEST of 10.1.5.255 on eth0 to 255.255.255.255 port 67
Apr 12 19:42:46 ubuntu dhclient: DHCPOFFER of 10.1.5.255 from 10.1.0.1
Apr 12 19:42:46 ubuntu dhclient: DHCPOFFER from 10.1.3.48 rejected by rule 10.1.3.48 mask 255.255.255.255.
Apr 12 19:42:46 ubuntu dhclient: DHCPACK of 10.1.5.255 from 10.1.0.1
Apr 12 19:42:46 ubuntu dhclient: bound to 10.1.5.255 -- renewal in 43104 seconds.
Apr 12 19:42:46 ubuntu kernel: [ 8.512887] init: failsafe main process (745) killed by TERM signal
Apr 12 19:42:46 ubuntu kernel: [ 8.551401] type=1400 audit(1365820966.336:8): apparmor="STATUS" operation="profile_replace" name="/sbin/dhclient" pid=866 comm="apparmor_parser"
Apr 12 19:42:46 ubuntu kernel: [ 8.552253] type=1400 audit(1365820966.340:9): apparmor="STATUS" operation="profile_replace" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=866 comm="apparmor_parser"
Apr 12 19:42:46 ubuntu kernel: [ 8.552723] type=1400 audit(1365820966.340:10): apparmor="STATUS" operation="profile_replace" name="/usr/lib/connman/scripts/dhclient-script" pid=866 comm="apparmor_parser"
Apr 12 19:42:46 ubuntu kernel: [ 8.562192] type=1400 audit(1365820966.348:11): apparmor="STATUS" operation="profile_load" name="/usr/sbin/tcpdump" pid=868 comm="apparmor_parser"
Apr 12 19:42:46 ubuntu cron[895]: (CRON) INFO (pidfile fd = 3)
Apr 12 19:42:46 ubuntu mdadm[910]: DeviceDisappeared event detected on md device /dev/md/0, component device Wrong-Level
Apr 12 19:42:46 ubuntu cron[920]: (CRON) STARTUP (fork ok)
Apr 12 19:42:46 ubuntu cron[920]: (CRON) INFO (Running @reboot jobs)
Apr 12 19:42:54 ubuntu ntpdate[818]: adjust time server 91.189.94.4 offset 0.188979 sec
Apr 12 19:42:56 ubuntu kernel: [ 18.721994] eth0: no IPv6 routers present
Apr 12 19:43:12 ubuntu kernel: [ 35.070907] usb 1-5.3: reset high-speed USB device number 4 using ehci_hcd
Apr 12 19:43:23 ubuntu kernel: [ 45.212938] usb 1-5.3: reset high-speed USB device number 4 using ehci_hcd
Apr 12 19:43:39 ubuntu kernel: [ 61.354018] usb 1-5.3: reset high-speed USB device number 4 using ehci_hcd
Apr 12 19:43:39 ubuntu kernel: [ 61.521613] usb 1-5.3: reset high-speed USB device number 4 using ehci_hcd
Apr 12 19:43:49 ubuntu kernel: [ 71.663780] usb 1-5.3: reset high-speed USB device number 4 using ehci_hcd
Apr 12 19:43:49 ubuntu kernel: [ 71.756135] sr 6:0:0:0: Device offlined - not ready after error recovery
Apr 12 19:43:49 ubuntu kernel: [ 71.756166] sr 6:0:0:0: rejecting I/O to offline device
Apr 12 19:43:49 ubuntu kernel: [ 71.756722] sr0: scsi3-mmc drive: 0x/0x caddy
Apr 12 19:43:49 ubuntu kernel: [ 71.756726] cdrom: Uniform CD-ROM driver Revision: 3.20
Apr 12 19:43:49 ubuntu kernel: [ 71.756951] sr 6:0:0:0: Attached scsi CD-ROM sr0
Apr 12 19:43:49 ubuntu kernel: [ 71.757034] sr 6:0:0:0: rejecting I/O to offline device
Apr 12 19:43:49 ubuntu kernel: [ 71.757643] sr 6:0:0:0: Attached scsi generic sg2 type 5
Apr 12 19:43:49 ubuntu kernel: [ 71.778813] sr 6:0:0:0: rejecting I/O to offline device
Apr 12 19:43:49 ubuntu kernel: [ 71.779394] sr 6:0:0:0: rejecting I/O to offline device
Apr 12 19:43:49 ubuntu kernel: [ 71.779972] sr 6:0:0:0: rejecting I/O to offline device
Apr 12 19:43:49 ubuntu kernel: [ 71.780829] sr 6:0:0:0: rejecting I/O to offline device
更新：
@jordanm 和其他人 - 正确，我刚刚确认这是 CDROM 设备，但这是由先前的 KVM 会话通过服务器上的 IPMI 创建的“虚拟 CD”。它不再存在了，知道如何摆脱它吗？或者不尝试访问它，我不确定它为什么在那里。