Hammer, usb disk, SYNCHRONIZE CACHE failure

Michael Neumann mneumann at ntecs.de
Wed Apr 8 13:50:09 PDT 2009

Matthew Dillon wrote:

> :This is for 2.2-RELEASE.  I have a 2.5" drive in an external USB
> :enclosure with one big Hammer filesystem on it.  The disk is ~75GB.
> :When the daily cronjob to cleanup hammer runs it fails with these
> :errors:
> :
> :Thanks,
> :Joe
>     I'm not sure what's going on here.  HAMMER does issue a synchronize
>     cache
>     op but it should be ignoring the error.  Maybe the recovery from the
>     unsupported synchronize cache op is causing a later write op to fail.

I think there are devices that claim to support this operation but in 
reality do not support it. Or something like this. FreeBSD has a quirk file 
for this. For example my Seagate USB disk always prints those synchronize 
cache failure messages on FreeBSD. Look out for NO_SYNCHRONIZE_CACHE
in this file:




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