Lowell Gilbert <[EMAIL PROTECTED]> writes: >We keep trying to point out that barriers *can't* be enforced on the >hardware with many (most, and apparently an increasing percentage of) >ATA drives. There is no semantic on these drives that allows you to >guarantee the journal block will be written before the corresponding >data block. If you are sure that your drives do this properly, then >you are safe, but in that case there's no reliability problem with >softupdates, either.
See my other mail(s) about other systems using cache disabling/enabling to make up for a drive that ignores (or does not implement) a flush command. Then the advice of "disable the wb-cache on disks to ensure data safety" doesn't make sense: Either * the drive supports disabling the write-back-cache, then this method can be used to flush data to the platters, or else * the drive does not support disabling the write-back-cache, or lies about it, then the advice to disable the write-back-cache for softupdates is meaningless. I know my drive allows disabling of the write cache, as, apparently, the majority of IDE/SATA drives do. mkb. _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "[EMAIL PROTECTED]"
