I am using golang guestfs binding. I am exploring Copy_in and Rsync_in functions. While doing copy/sync of large files/dirs from local to image(qcow2 image), it takes a lot of time.
I went through the official document and this and it recommends to create the iso and attach the created iso as an extra disk. This really improves the performance as I don't need to do the Copy_in or Rsync_in. I can use the cp-a or cp-r(it will be like copying locally from mounted iso to mounted qcow2)
But again there is an overhead of creating iso. genisoimage/mkisofs takes lot of time(approx 6 mins for 10Gi data with around 2 cpus and 3 Gi memory).
Is there any way to improve the Copy_in/Rsync_in performance? or is there any way to make the iso creation process faster?