Re: geom_journal - bio_flush not supported on disks connected via usb?

On Mon, Jul 30, 2007 at 03:58:02PM +0200, Marc UBM Bocklet wrote:
> 
> Hiho! :-)
> 
> 
> During startup, I got this error (only once):
> 
> 
> GEOM_JOURNAL: Journal 1159150689: da0 contains data.
> GEOM_JOURNAL: Journal 1159150689: da0 contains journal.
> GEOM_JOURNAL: Journal da0 clean.
> (da0:umass-sim0:0:0:0): SYNCHRONIZE CACHE. CDB: 35 0 0 0 0 0 0 0 0 0 
> (da0:umass-sim0:0:0:0): CAM Status: SCSI Status Error
> (da0:umass-sim0:0:0:0): SCSI Status: Check Condition
> (da0:umass-sim0:0:0:0): ILLEGAL REQUEST asc:20,0
> (da0:umass-sim0:0:0:0): Invalid command operation code
> (da0:umass-sim0:0:0:0): Unretryable error
> GEOM_JOURNAL: BIO_FLUSH not supported by da0.
> 
> 
> da0 is 250GB usb disk (using ehci(4)).
> 
> I do not understand completely what this means. Has the BIO_FLUSH
> command only failed once and works now on subsequent tries?

No, it means that gjournal tried it once and now knows that it's not
supported, so won't spam you console again.

> Does BIO_FLUSH never work, because it's not implemented (or can't be
> implemented) for disks connected via usb? And if thats the case, will
> that affect geom_journal in any way? Is my data still being journalled
> correctly? :-)

If write cache is turned on on your disk, there can be a problem in case
of a power failure. I don't know how write cache is beeing turned on for
a disk connected via USB. Is it turned on by default? If it's turned off
by default, then you are safe.

-- 
Pawel Jakub Dawidek                       http://www.wheel.pl
pjd_at_FreeBSD.org                           http://www.FreeBSD.org
FreeBSD committer                         Am I Evil? Yes, I Am!