Hi All, I'm facing a really slow export ov vms hosted on a single node cluster, in a local storage. The Vm disk is 600 GB and the effective usage is around 300 GB. I estimated that the following process would take up about 15 hours to end: vdsm 25338 25332 99 04:14 pts/0 07:40:09 qemu-img measure -O qcow2 /rhev/data-center/mnt/_data/6775c41c-7d67-451b-8beb-4fd086eade2e/images/a084fa36-0f93-45c2-a323-ea9ca2d16677/55b3eac5-05b2-4bae-be50-37cde7050697 A strace -p of the pid shows a slow progression to reach the effective size. lseek(11, 3056795648, SEEK_DATA) = 3056795648 lseek(11, 3056795648, SEEK_HOLE) = 13407092736 lseek(14, 128637468672, SEEK_DATA) = 128637468672 lseek(14, 128637468672, SEEK_HOLE) = 317708828672 lseek(14, 128646250496, SEEK_DATA) = 128646250496 lseek(14, 128646250496, SEEK_HOLE) = 317708828672 lseek(14, 128637730816, SEEK_DATA) = 128637730816 lseek(14, 128637730816, SEEK_HOLE) = 317708828672 lseek(14, 128646774784, SEEK_DATA) = 128646774784 lseek(14, 128646774784, SEEK_HOLE) = 317708828672 lseek(14, 128646709248, SEEK_DATA) = 128646709248 The process take a single full core, but i don't think this is the problem. The I/O is almost nothing. Any idea/suggestion? Thank you for your time Regards