Re: Why is a wedge on RAID 10x slower?

[Patrick Welche <prlw1%cam.ac.uk@localhost>]

On Wed, Nov 30, 2016 at 11:30:51AM +0000, Stephen Borrill wrote:
> mlelstv pointed out that because of the 64 sectPerSU RAIDframe setting (i.e.
> 128 sectors of data with 3 components, or 64k), the stripe unit is 32k, but
> the whole stripe is 64k. By starting the wedge at 64 sectors,
> this is 32k, but I'm attempting to do 64k I/O. Therefore the wedge should
> start at 128, not 64
> 
> # dkctl raid0 addwedge bigdata 128 15628073823 ffs
> dk3 created successfully.

To check: this means the bigdata wedge on raid0 has to be correctly aligned,
but the raid0 wedge on wd0 doesn't need to be?

Cheers,

Patrick