On Wed, Dec 9, 2009 at 5:43 PM, Neil Brown <neilb@xxxxxxx> wrote: > On Wed, 9 Dec 2009 19:29:04 +0800 > hank peng <pengxihan@xxxxxxxxx> wrote: > >> I think it is better to implement this function in kernel's md layer. >> I wonder what Neil Brown think of this? > > I don't think it is worth the effort. > You probably would save some CPU time as you don't need to XOR, but as has > been said, we are usually IO bound, not CPU bound. > > With the current arrangement, you can start using the array immediately - you > don't have to wait for the initial recovery to complete. > If you zeroed all devices at create time, you would have to wait for that to > complete before using the array. > > So I see very little gain, and significant cost. > > NeilBrown > > When I assemble an array I tend to have checked the devices before hand; it would not be difficult to make the final pass a zeroing pass if I knew I could vastly speed up post-assembly performance. As I stated, it's merely a lack of clarity in the documentation. -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
