>>> Indeed, performance traces are important for issues like this. >>See strace of both FC27 and FC29 attached
>Looks like you traced only the main thread. All the I/O is done in other >threads. >These flags would be useful: > > strace -o log -f -T -tt New straces attached with mentioned flags. Both truncated due to file size at what I believe to be the same position in the "write-phase". FC29 has the "zeroing-phase" in front. Fred
fc27_qemu-img.strace.snip.gz
Description: fc27_qemu-img.strace.snip.gz
fc29_qemu-img.strace.snip.gz
Description: fc29_qemu-img.strace.snip.gz