透過 USB 連接到我的系統 (Debian 7) 的 RAID 陣列經常無緣無故地自行斷開連接。初次連接到系統後，會偵測到該設備，並且可以正常初始化、安裝、讀取、寫入和卸載陣列。然而，在短時間（幾分鐘到幾小時）之後，元件磁碟總是會從/dev清單中消失fdisk -l，並且在裝置（即 RAID 儲存裝置）重新啟動之前保持無法存取狀態。
從 的輸出來看/var/log/messages，問題似乎出在 USB 裝置的重置。無端重置後，系統會反覆嘗試重新連接設備，分配更高的 USB 設備編號，最終在五次重置嘗試後終止。
是什麼導致設備自行重置？我懷疑問題出在USB控制器。如何避免不被期望的自動重置行為？
以下摘錄/var/log/messages顯示了初始化和後續重置後陣列的典型行為：
初始連線：
Jun 19 19:38:51 hostname kernel: [406823.308418] usb 1-1.3: new high-speed USB device number 24 using ehci_hcd
Jun 19 19:38:51 hostname kernel: [406823.401317] usb 1-1.3: New USB device found, idVendor=152d, idProduct=2351
Jun 19 19:38:51 hostname kernel: [406823.401330] usb 1-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=5
Jun 19 19:38:51 hostname kernel: [406823.401338] usb 1-1.3: Product: USB to ATA/ATAPI Bridge
Jun 19 19:38:51 hostname kernel: [406823.401345] usb 1-1.3: Manufacturer: JMicron
Jun 19 19:38:51 hostname kernel: [406823.401350] usb 1-1.3: SerialNumber: DCC3..........
Jun 19 19:38:51 hostname kernel: [406823.402469] scsi16 : usb-storage 1-1.3:1.0
Jun 19 19:38:51 hostname mtp-probe: checking bus 1, device 24: "/sys/devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.3"
Jun 19 19:38:51 hostname mtp-probe: bus: 1, device: 24 was not an MTP device
Jun 19 19:38:52 hostname kernel: [406824.400835] scsi 16:0:0:0: Direct-Access WDC WD20 EFRX-68AX9N0 PQ: 0 ANSI: 5
Jun 19 19:38:52 hostname kernel: [406824.401450] scsi 16:0:0:1: Direct-Access WDC WD20 EFRX-68AX9N0 PQ: 0 ANSI: 5
Jun 19 19:38:52 hostname kernel: [406824.402433] sd 16:0:0:0: Attached scsi generic sg2 type 0
Jun 19 19:38:52 hostname kernel: [406824.402583] sd 16:0:0:1: Attached scsi generic sg3 type 0
Jun 19 19:38:52 hostname kernel: [406824.662288] sd 16:0:0:0: [sdd] 3907029168 512-byte logical blocks: (2.00 TB/1.81 TiB)
Jun 19 19:38:52 hostname kernel: [406824.662789] sd 16:0:0:1: [sde] 3907029168 512-byte logical blocks: (2.00 TB/1.81 TiB)
Jun 19 19:38:52 hostname kernel: [406824.663573] sd 16:0:0:0: [sdd] Write Protect is off
Jun 19 19:38:52 hostname kernel: [406824.664356] sd 16:0:0:1: [sde] Write Protect is off
Jun 19 19:38:52 hostname kernel: [406824.665087] sd 16:0:0:0: [sdd] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
Jun 19 19:38:52 hostname kernel: [406824.666295] sd 16:0:0:1: [sde] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
Jun 19 19:38:52 hostname kernel: [406824.705355] sdd: sdd1
Jun 19 19:38:52 hostname kernel: [406824.740148] sde: sde1
Jun 19 19:38:52 hostname kernel: [406824.743667] sd 16:0:0:0: [sdd] Attached SCSI disk
Jun 19 19:38:52 hostname kernel: [406824.746756] sd 16:0:0:1: [sde] Attached SCSI disk
重置後：
Jun 19 20:05:25 hostname kernel: [408416.587392] usb 1-1.3: reset high-speed USB device number 24 using ehci_hcd
Jun 19 20:05:25 hostname kernel: [408416.679688] usb 1-1.3: device firmware changed
Jun 19 20:05:25 hostname kernel: [408416.679852] sd 16:0:0:0: Device offlined - not ready after error recovery
Jun 19 20:05:25 hostname kernel: [408416.679942] usb 1-1.3: USB disconnect, device number 24
Jun 19 20:05:25 hostname kernel: [408416.767366] usb 1-1.3: new high-speed USB device number 25 using ehci_hcd
Jun 19 20:05:25 hostname kernel: [408416.860214] usb 1-1.3: New USB device found, idVendor=152d, idProduct=2351
Jun 19 20:05:25 hostname kernel: [408416.860225] usb 1-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=5
Jun 19 20:05:25 hostname kernel: [408416.860232] usb 1-1.3: Product: USB to ATA/ATAPI Bridge
Jun 19 20:05:25 hostname kernel: [408416.860237] usb 1-1.3: Manufacturer: JMicron
Jun 19 20:05:25 hostname kernel: [408416.860241] usb 1-1.3: SerialNumber: 152D.............
Jun 19 20:05:25 hostname kernel: [408416.861634] scsi17 : usb-storage 1-1.3:1.0
Jun 19 20:05:25 hostname mtp-probe: checking bus 1, device 25: "/sys/devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.3"
Jun 19 20:05:25 hostname mtp-probe: bus: 1, device: 25 was not an MTP device
Jun 19 20:05:47 hostname kernel: [408438.591825] usb 1-1.3: reset high-speed USB device number 25 using ehci_hcd
Jun 19 20:05:57 hostname kernel: [408448.750695] usb 1-1.3: reset high-speed USB device number 25 using ehci_hcd
Jun 19 20:06:02 hostname kernel: [408453.911854] usb 1-1.3: reset high-speed USB device number 25 using ehci_hcd
Jun 19 20:06:03 hostname kernel: [408454.359608] usb 1-1.3: reset high-speed USB device number 25 using ehci_hcd
Jun 19 20:06:03 hostname kernel: [408454.807394] usb 1-1.3: reset high-speed USB device number 25 using ehci_hcd
Jun 19 20:06:04 hostname kernel: [408455.295168] usb 1-1.3: reset high-speed USB device number 25 using ehci_hcd
Jun 19 20:06:04 hostname kernel: [408455.711201] scsi 17:0:0:0: Device offlined - not ready after error recovery
Jun 19 20:06:04 hostname kernel: [408455.711448] usb 1-1.3: USB disconnect, device number 25
Jun 19 20:06:04 hostname kernel: [408455.786917] usb 1-1.3: new high-speed USB device number 26 using ehci_hcd
Jun 19 20:06:05 hostname kernel: [408456.234679] usb 1-1.3: new high-speed USB device number 27 using ehci_hcd
Jun 19 20:06:05 hostname kernel: [408456.686418] usb 1-1.3: new high-speed USB device number 28 using ehci_hcd
Jun 19 20:06:06 hostname kernel: [408457.174018] usb 1-1.3: new high-speed USB device number 29 using ehci_hcd
嘗試指派 USB 裝置編號 29 是復原磁碟陣列的最後一次嘗試。若要在此時重新連接設備，必須重新啟動 RAID 儲存設備或斷開/重新連線。
更新：最近，設備似乎在重新同步後不久就重置了。我不確定這是否有幫助，但其中包含的錯誤訊息/var/log/messages如下：
Jul 5 02:55:02 hdac kernel: [135732.758796] md: md0: resync done.
Jul 5 03:12:04 hdac kernel: [136754.176970] usb 1-1.3: reset high-speed USB device number 10 using ehci_hcd
Jul 5 03:12:04 hdac kernel: [136754.269537] usb 1-1.3: device firmware changed
Jul 5 03:12:04 hdac kernel: [136754.269995] usb 1-1.3: USB disconnect, device number 10
Jul 5 03:12:04 hdac kernel: [136754.269998] sd 6:0:0:1: Device offlined - not ready after error recovery
Jul 5 03:12:04 hdac kernel: [136754.348882] usb 1-1.3: new high-speed USB device number 11 using ehci_hcd
Jul 5 03:12:04 hdac kernel: [136754.442408] usb 1-1.3: New USB device found, idVendor=152d, idProduct=2351
Jul 5 03:12:04 hdac kernel: [136754.442419] usb 1-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=5
Jul 5 03:12:04 hdac kernel: [136754.442425] usb 1-1.3: Product: USB to ATA/ATAPI Bridge
Jul 5 03:12:04 hdac kernel: [136754.442430] usb 1-1.3: Manufacturer: JMicron
Jul 5 03:12:04 hdac kernel: [136754.442434] usb 1-1.3: SerialNumber: 152D....
Jul 5 03:12:04 hdac kernel: [136754.443581] scsi7 : usb-storage 1-1.3:1.0
Jul 5 03:12:04 hdac mtp-probe: checking bus 1, device 11: "/sys/devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.3"
Jul 5 03:12:04 hdac mtp-probe: bus: 1, device: 11 was not an MTP device
Jul 5 03:12:26 hdac kernel: [136776.197464] usb 1-1.3: reset high-speed USB device number 11 using ehci_hcd
Jul 5 03:12:36 hdac kernel: [136786.356068] usb 1-1.3: reset high-speed USB device number 11 using ehci_hcd
Jul 5 03:12:41 hdac kernel: [136791.517429] usb 1-1.3: reset high-speed USB device number 11 using ehci_hcd
Jul 5 03:12:42 hdac kernel: [136791.965221] usb 1-1.3: reset high-speed USB device number 11 using ehci_hcd
Jul 5 03:12:42 hdac kernel: [136792.412974] usb 1-1.3: reset high-speed USB device number 11 using ehci_hcd
Jul 5 03:12:43 hdac kernel: [136792.900701] usb 1-1.3: reset high-speed USB device number 11 using ehci_hcd
Jul 5 03:12:43 hdac kernel: [136793.316865] scsi 7:0:0:0: Device offlined - not ready after error recovery
Jul 5 03:12:43 hdac kernel: [136793.317120] usb 1-1.3: USB disconnect, device number 11
Jul 5 03:12:43 hdac kernel: [136793.388401] usb 1-1.3: new high-speed USB device number 12 using ehci_hcd
Jul 5 03:12:44 hdac kernel: [136793.836359] usb 1-1.3: new high-speed USB device number 13 using ehci_hcd
Jul 5 03:12:44 hdac kernel: [136794.283982] usb 1-1.3: new high-speed USB device number 14 using ehci_hcd
Jul 5 03:12:45 hdac kernel: [136794.776418] usb 1-1.3: new high-speed USB device number 15 using ehci_hcd
Jul 5 07:46:51 hdac rsyslogd: [origin software="rsyslogd" swVersion="5.8.11" x-pid="2234" x-info="http://www.rsyslog.com"] rsyslogd was HUPed
Jul 5 07:46:51 hdac kernel: [153233.051604] md: super_written gets error=-19, uptodate=0
Jul 5 07:46:51 hdac kernel: [153233.080561] lost page write due to I/O error on md0
Jul 5 07:46:51 hdac kernel: [153233.082218] lost page write due to I/O error on md0
Jul 5 07:46:51 hdac kernel: [153233.088909] lost page write due to I/O error on md0
Jul 5 07:46:51 hdac kernel: [153233.088972] lost page write due to I/O error on md0
Jul 5 07:46:51 hdac kernel: [153233.089030] lost page write due to I/O error on md0
Jul 5 07:46:51 hdac kernel: [153233.089084] lost page write due to I/O error on md0
Jul 5 07:46:51 hdac kernel: [153233.089139] lost page write due to I/O error on md0
Jul 5 07:46:51 hdac kernel: [153233.089193] lost page write due to I/O error on md0
Jul 5 07:46:51 hdac kernel: [153233.089247] lost page write due to I/O error on md0
Jul 5 07:46:51 hdac kernel: [153233.089300] lost page write due to I/O error on md0
Jul 5 07:46:52 hdac kernel: [153233.308299] md: super_written gets error=-19, uptodate=0
Jul 5 15:04:02 hdac kernel: [179450.340233] md: super_written gets error=-19, uptodate=0
Jul 5 15:04:02 hdac kernel: [179450.340549] quiet_error: 101 callbacks suppressed
Jul 5 15:04:02 hdac kernel: [179450.340566] lost page write due to I/O error on md0
Jul 5 15:04:02 hdac kernel: [179450.340774] lost page write due to I/O error on md0
Jul 5 15:04:03 hdac kernel: [179450.541182] md: super_written gets error=-19, uptodate=0
Jul 5 15:04:08 hdac kernel: [179455.698562] md: super_written gets error=-19, uptodate=0
Jul 5 15:04:08 hdac kernel: [179455.699059] lost page write due to I/O error on md0
Jul 5 15:04:08 hdac kernel: [179455.902387] md: super_written gets error=-19, uptodate=0
Jul 5 15:04:32 hdac kernel: [179479.848336] md: super_written gets error=-19, uptodate=0
Jul 5 15:04:32 hdac kernel: [179479.848803] lost page write due to I/O error on md0
Jul 5 15:04:32 hdac kernel: [179479.848832] lost page write due to I/O error on md0
Jul 5 15:04:32 hdac kernel: [179480.049689] md: super_written gets error=-19, uptodate=0
Jul 5 15:20:11 hdac kernel: [180418.849041] md: super_written gets error=-19, uptodate=0
Jul 5 15:20:11 hdac kernel: [180418.852710] lost page write due to I/O error on md0
Jul 5 15:20:12 hdac kernel: [180419.056405] md: super_written gets error=-19, uptodate=0