Il 17/06/2014 13:37, Peter Lieven ha scritto:
On 17.06.2014 13:15, Paolo Bonzini wrote:
Il 17/06/2014 08:14, Peter Lieven ha scritto:
BTW, while debugging a case with a bigger storage supplier I found
that open-iscsi seems to do exactly this undeterministic behaviour.
I have a 3TB LUN. If I access < 2TB sectors it uses READ10/WRITE10 and
if I go beyond 2TB it changes to READ16/WRITE16.
Isn't that exactly what your latest patch does for >64K sector writes? :)
Not exactly, we choose the default by checking the LUN size. 10 Byte for
< 2TB and 16 Byte otherwise.
Yeah, I meant introducing the non-determinism.
My latest patch makes an exception if a request is bigger than 64K
sectors and
switches to 16 Byte requests. These would otherwise end in an I/O error.
It could also be split at the block layer, like we do for unmap. I
think there's also a maximum transfer size somewhere in the VPD, we
could to READ16/WRITE16 if it is >64K sectors.
Paolo
