> 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 [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
