[Qemu-devel] fstrim and cache=none

[Dusty Mabe]

Hi,

Is it valid to have cache=none and discard=unmap together? I notice
that when I have cache=none the fstrim operations inside of my guests
gives me an error and i get this from the sys filesystem:

address@hidden ~]# cat /sys/block/sdb/queue/discard*
4096
0
0


This wasn't very obvious to me to begin with and just wanted to see if
this is a bug or as designed.


libvirt 1.0.6
qemu 1.5.0

Thanks,
Dusty