> On Nov 03, 2006 15:30 +0100, Jan Kara wrote: > > > - stripe unit and stripe width need to be exposed so defrag too > > > can make correct placement decisions. > > fs-specific thing... > > I think this is not just XFS-specific. It is very desirable to align > large IO to the RAID stripe so that if you write stripe_width bytes > you don't do 2 expensive read-modify-write steps, but rather a single > write operation. Also RAID controllers have (large) internal cache > "lines" and having aligned reads can help noticably, and also if array > is doing RAID parity checking to avoid overhead of doing this for two > stripes instead of one. I see, thanks for information. On the other hand this is rather an underlying block device feature than a fs thing, isn't it? So does it make sence to pass this information via fs interface? Honza - 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
