Re: SCSI Write Cache Enable in 2.4.20?

[Jeff Garzik]

Cress, Andrew R wrote:
> IMO, it isn't "necessary", but it is very desirable, and should be the
> default, to disable write cache on SCSI disks for any system that is
> concerned about reliability.

This sounds like a bug, either in an application, or in Linux kernel's 
scsi disk implementation.

Data is only guaranteed to be written onto disk following an 
fsync(2)-like operation in the application.  And in turn, it is the 
Linux kernel's responsibility to ensure that such a flush is propagated 
all the down to the low-level driver, in my opinion.  Sophisticated 
hosts can have barriers, and "dumb" hosts can simply call the drive's 
flush-cache / sync-cache command.

	Jeff