Thanks. I have applied this patch. NeilBrown On Wed, 9 Dec 2009 21:52:18 -0800 (PST) mjevans1983@xxxxxxxxx wrote: > On Wed, Dec 9, 2009 at 7:59 PM, Neil Brown <neilb@xxxxxxx> wrote: > > On Wed, 9 Dec 2009 19:34:04 -0800 > > Michael Evans <mjevans1983@xxxxxxxxx> wrote: > > > >> 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. > > > > If you would like to create a patch against the man page, I would be happy to > > accept it. > > > > NeilBrown > > > > diff --git a/mdadm.8 b/mdadm.8 > index f8f240a..29e098b 100644 > --- a/mdadm.8 > +++ b/mdadm.8 > @@ -648,6 +648,12 @@ data will be affected unless you actually write to the array. It can > also be used when creating a RAID1 or RAID10 if you want to avoid the > initial resync, however this practice \(em while normally safe \(em is not > recommended. Use this only if you really know what you are doing. > +.IP > +When the devices that will be part of a new array were filled > +with zeros before creation the operator knows the array is > +actually clean. If that is the case, such as after running > +badblocks, this argument can be used to tell mdadm the > +facts the operator knows. > > .TP > .BR \-\-backup\-file= -- 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
