當我使用 USB 2.0 連接埠將 Fantec DB-ALUE2e 外部 SATA 機箱中的 Hitachi Deskstar 7K4000 4TB 硬碟機連接到 Lenovo T400 筆記型電腦時，該硬碟被分成 2 個裝置：
[ 1537.560160] usb 1-1: new high speed USB device using ehci_hcd and address 4
[ 1537.714687] usb 1-1: configuration #1 chosen from 1 choice
[ 1537.814573] Initializing USB Mass Storage driver...
[ 1537.814847] scsi4 : SCSI emulation for USB Mass Storage devices
[ 1537.815088] usbcore: registered new interface driver usb-storage
[ 1537.815094] USB Mass Storage support registered.
[ 1537.815818] usb-storage: device found at 4
[ 1537.815823] usb-storage: waiting for device to settle before scanning
[ 1542.810488] usb-storage: device scan complete
[ 1542.812251] scsi 4:0:0:0: Direct-Access Generic External 0200 PQ: 0 ANSI: 4
[ 1542.813976] scsi 4:0:0:1: Direct-Access Generic External 0200 PQ: 0 ANSI: 4
[ 1542.818156] sd 4:0:0:0: Attached scsi generic sg2 type 0
[ 1542.820658] sd 4:0:0:1: Attached scsi generic sg3 type 0
[ 1542.822331] sd 4:0:0:0: [sdb] 4294967295 512-byte logical blocks: (2.19 TB/1.99 TiB)
[ 1542.829215] sd 4:0:0:0: [sdb] Write Protect is off
[ 1542.829224] sd 4:0:0:0: [sdb] Mode Sense: 38 00 00 00
[ 1542.829229] sd 4:0:0:0: [sdb] Assuming drive cache: write through
[ 1542.830485] sd 4:0:0:1: [sdc] 3519069872 512-byte logical blocks: (1.80 TB/1.63 TiB)
[ 1542.838112] sd 4:0:0:1: [sdc] Write Protect is off
[ 1542.838120] sd 4:0:0:1: [sdc] Mode Sense: 38 00 00 00
[ 1542.838125] sd 4:0:0:1: [sdc] Assuming drive cache: write through
[ 1542.844988] sd 4:0:0:0: [sdb] Assuming drive cache: write through
[ 1542.844997] sdb:
[ 1542.876247] sd 4:0:0:1: [sdc] Assuming drive cache: write through
[ 1542.876255] sdc: unknown partition table
[ 1542.901098] unknown partition table
[ 1542.907979] sd 4:0:0:0: [sdb] Assuming drive cache: write through
[ 1542.907988] sd 4:0:0:0: [sdb] Attached SCSI disk
[ 1542.916738] sd 4:0:0:1: [sdc] Assuming drive cache: write through
[ 1542.916746] sd 4:0:0:1: [sdc] Attached SCSI disk
我已經在 Linux 核心 2.6.32、2.6.35 和 3.6.6 上嘗試過此操作。
如果我透過 eSATA 連接它，整個裝置就會被辨識：
[3867153.075703] sd 9:0:0:0: [sdd] 7814037168 512-byte logical blocks: (4.00 TB/3.63 TiB)
[3867153.075708] sd 9:0:0:0: [sdd] 4096-byte physical blocks
[3867153.075862] sd 9:0:0:0: [sdd] Write Protect is off
[3867153.075868] sd 9:0:0:0: [sdd] Mode Sense: 00 3a 00 00
[3867153.075906] sd 9:0:0:0: [sdd] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[3867153.082355] sdd: unknown partition table
[3867153.098386] sd 9:0:0:0: [sdd] Attached SCSI disk
奇怪的是，缺少 1 個扇區：7814037168 - 4294967295 - 3519069872 == 1。
我的問題：
- 這是 USB 大容量儲存 (usb-storage) 協定的固有限制（單一裝置最多可達 2 TB - 512 位元組），還是 Fantec 外部外殼的限制，或者是 Linux 核心問題？
- 這是 USB 大容量儲存 (usb-storage) 協定的固有限制嗎？ Fantec 外部外殼的限制——還是Linux 內核問題？
- 使用 USB 3.0 會更好嗎？
答案1
- 我不認為 USB 大容量儲存協定有任何限制。市場上有超過 2TB 的外部驅動器，帶有 USB 接口，可以在單一磁碟區上正常工作。
- 我不認為 USB 海量儲存協定有磁區大小限制，因為有一個帶有 USB 介面的希捷外接 3TB 硬碟，已知可以報告 4K 邏輯磁區。
- 我懷疑 USB 3.0 會更好
我認為您的問題出在外殼中的 USB<--->SATA 橋接晶片上。它必須將 SATA 磁碟機正在使用的 ATA 派生命令與 USB 正在使用的 SCSI 派生命令橋接上。我不知道為什麼它顯然將物理驅動器分成兩個邏輯驅動器。嘗試另一個外殼。