> > If you fsync() your data, you are guaranteed that also your data are > >safely on disk when fsync returns. So what is the question here? > Pardon a newbie's intrusion, but I do know this isn't true. There is a > window of possible loss because of the multitude of layers of caching, > especially within the drive itself. Unless there is a super_duper_fsync() > that is able to actually poll the hardware and get a confirmation that the > internal buffers are purged? OK :), to correct myself: After fsync() returns, all the data is acked from the disk (or at least it should be like that unless there's a bug somewhere). So if there are some caches in the hardware which the hardware is not able to flush on power failure, that's a bad luck... That's why you should turn off write caching on cheaper disks if you really care about data integrity. Honza -- Jan Kara <jack@xxxxxxx> SuSE CR Labs - To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
