Correct way to disconnect/eject an USB hard disk ?

[Christoph Kukulies]

I had this /dev/da4 external USB drive connected to the system and had mounted
/dev/da4s3 to /mnt.

After unmounting, are there any other measures to cleanly disconnect the device?

I found that someone wrote to use

camcontrol eject <dev>

This is my picture:

dev/da0	/dev/da3	/dev/da4s2	/dev/da5
/dev/da1	/dev/da4	/dev/da4s3	/dev/da5p1
/dev/da2	/dev/da4s1	/dev/da4s4	/dev/da5p2
# camcontrol devlist
<KINGSTON SA400S37240G SBFKB1D1>   at scbus0 target 0 lun 0 (ada0,pass0)
<WDC WD10EADS-22M2B0 01.00A01>     at scbus1 target 0 lun 0 (ada1,pass1)
<Samsung SSD 840 EVO 120GB EXT0AB0Q>  at scbus2 target 0 lun 0 (ada2,pass2)
<SAMSUNG HD502HJ 1AJ100E4>         at scbus3 target 0 lun 0 (ada3,pass3)
<HL-DT-ST DVDRAM GH24NSD5 LV00>    at scbus4 target 0 lun 0 (cd0,pass4)
<CREATIVE CD5230E 1.01>            at scbus6 target 1 lun 0 (cd1,pass5)
<HD0 SCSI2SD 4.2>                  at scbus7 target 0 lun 0 (da0,pass6)
<HD1 SCSI2SD 4.2>                  at scbus7 target 1 lun 0 (da1,pass7)
<HD2 SCSI2SD 4.2>                  at scbus7 target 2 lun 0 (da2,pass8)
<HD3 SCSI2SD 4.2>                  at scbus7 target 3 lun 0 (da3,pass9)
<WDC WD30 EFRX-68EUZN0 0107>       at scbus8 target 0 lun 0 (da4,pass10)
<WDC WD30 EZRX-00MMMB0 0107>       at scbus8 target 0 lun 1 (da5,pass11)
# camcontrol eject da4
Error received from stop unit command

?
—
Christoph

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