how to remove usb-storage devices without CAM errors

[Ronald Klop]

On Thu, 08 Aug 2013 05:56:21 +0200, Michael Schuh  
<michael.schuh at gmail.com> wrote:

> H i at list,
>
> i have a simple wuestion caused by a "device loss".
>
> is there a special routine for unplugging usb-storage devices?
> in the meaning:
> may be settle some commends before unplugging the device
> other than umount.
> according to the handbook there ist no special routine.
> unmounting should be enough and pull the USB-Devie out of the bus.
>
> i could not find anything related by the help of the big oracle.
>
>
> i have some usb-sticks that i need to write with prepared disk-images by
> using dd.
> two or more drives are already plugged in
> and da0 is already finished, da1 or da2 still at writing.
> unplugging da0 causes a CAM error and interrupts the ongoing write.
> i am not sure if all writes to each different device gets stopped.
> this is a reproduceable behaviour thats new to me.
> see the listing below.
>
> let me know if i can and what to do to help to further identify
> and investigate this error.
>
> iirc this happens for the first time this way.
> my last upgrade before this was feb./march.
> time of svn checkout was 2013-07-22 so its may be already fixed?
>
> many thanks in advance
>
> regards
>
> michael



Does 'camcontrol eject <device_id>' help? It tells CAM to eject the  
device. This is usefull for CD's, but maybe to for preventing errors for  
USB-storage.

Ronald.



>
> ===============
>
> ugen3.2: <Verbatim> at usbus3
> umass0: <Verbatim STORE N GO, class 0/0, rev 2.10/1.10, addr 2> on usbus3
> umass0:  SCSI over Bulk-Only; quirks = 0x0100
> umass0:8:0:-1: Attached to scbus8
> da0 at umass-sim0 bus 0 scbus8 target 0 lun 0
> da0: <Verbatim STORE N GO PMAP> Removable Direct Access SCSI-6 device
> da0: 40.000MB/s transfers
> da0: 7385MB (15124992 512 byte sectors: 255H 63S/T 941C)
> da0: quirks=0x2<NO_6_BYTE>
> ugen7.2: <Verbatim> at usbus7
> umass1: <Verbatim STORE N GO, class 0/0, rev 2.10/1.10, addr 2> on usbus7
> umass1:  SCSI over Bulk-Only; quirks = 0x0100
> umass1:9:1:-1: Attached to scbus9
> da1 at umass-sim1 bus 1 scbus9 target 0 lun 0
> da1: <Verbatim STORE N GO PMAP> Removable Direct Access SCSI-6 device
> da1: 40.000MB/s transfers
> da1: 7385MB (15124992 512 byte sectors: 255H 63S/T 941C)
> da1: quirks=0x2<NO_6_BYTE>
> (da0:umass-sim0:0:0:0): WRITE(10). CDB: 2a 00 00 02 44 80 00 00 80 00
> ugen3.2: <Verbatim> at usbus3 (disconnected)
> (da0:umass-sim0:0:0:0): CAM status: CCB request completed with an error
> umass0: (da0:at uhub3, port 3, addr 2 (disconnected)
> umass-sim0:0:0:0): Retrying command
> (da0:umass-sim0:0:0:0): WRITE(10). CDB: 2a 00 00 02 44 80 00 00 80 00
> (da0:umass-sim0:0:0:0): CAM status: CCB request completed with an error
> (da0:umass-sim0:0:0:0): Retrying command
> (da0:umass-sim0:0:0:0): WRITE(10). CDB: 2a 00 00 02 44 80 00 00 80 00
> (da0:umass-sim0:0:0:0): CAM status: CCB request completed with an error
> (da0:umass-sim0:0:0:0): CAM status: CCB request completed with an error
> (da0:umass-sim0:0:0:0): Error 5, Retries exhausted
> (da0:umass-sim0:0:0:0): SYNCHRONIZE CACHE(10). CDB: 35 00 00 00 00 00 00  
> 00
> 00 00
> (da0:umass-sim0:0:0:0): CAM status: CCB request completed with an error
> (da0:umass-sim0:0:0:0): Retrying command
> (da0:umass-sim0:0:0:0): SYNCHRONIZE CACHE(10). CDB: 35 00 00 00 00 00 00  
> 00
> 00 00
> (da0:umass-sim0:0:0:0): CAM status: CCB request completed with an error
> (da0:umass-sim0:0:0:0): Error 5, Retries exhausted
> (da0:umass-sim0:0:0:0): got CAM status 0x44
> (da0:umass-sim0:0:0:0): fatal error, failed to attach to device
> (da0:umass-sim0:0:0:0): lost device - 0 outstanding, 5 refs
> (da0:umass-sim0:0:0:0): removing device entry
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