is qcow virtual disks are cached somewhere?
by gglq000 from LinuxQuestions.org on (#5BGN7)
i am doing some development which involved hacking in MBR boot sector of HDD. For that I am repeatedly turning off the qemu guest VM, de-attach the virtual HDD with qcow image.
After that I do the hacking stuff by mounting it through nbd driver on host and write to its boot or MBR sector.
After that I re-attached back again to guest VM and boot back.
But changes I made while on host is not reflected when i boot back on guest and it is erratic sometimes it does and sometimes it does not.
This led me to believe there may be somewhere a cached image of qcow which the vm is booting off of, when I repeatedly turning off and on. I was wondering what is the possibilty of that and if so, where???


After that I do the hacking stuff by mounting it through nbd driver on host and write to its boot or MBR sector.
After that I re-attached back again to guest VM and boot back.
But changes I made while on host is not reflected when i boot back on guest and it is erratic sometimes it does and sometimes it does not.
This led me to believe there may be somewhere a cached image of qcow which the vm is booting off of, when I repeatedly turning off and on. I was wondering what is the possibilty of that and if so, where???