I was refering to bios reaching make_request in raid5.c .
I would be more precise.
I am dd'ing " dd if=/dev/md1 of=/dev/zero bs=1M count=1 skip=10"
I have added the following printk in make_request "printk ("%d:",bio->bi_size)"
I am getting sector sizes. 512:512:512:512:512....
I suppose they gathered in the elevator,
but still why so small ?

thank you
raz.

On 3/27/06, Neil Brown [off-list ref] wrote:

On Monday March 27, raziebe@gmail.com wrote:

quoted

i have playing with raid5 and i noticed that the arriving bios  sizes
are 1 sector.
why is that  and where is it set ?

bios arriving from where?

bios from the filesystem to the raid5 device will be whatever size the
fs wants to make them.

bios from the raid5 device to the component devices will always be 1
page (typically 8 sectors).  This is the size used by the stripe cache
which is used to synchronise everything.

NeilBrown

--
Raz