ZFS has https://github.com/zfsonlinux/zfs/issues/326 Which as TL;DR: fallocate is only supported with certain flags, and not really matches the ZFS COW design. That might explain the slowness, as the fallback is to write zeros.
** Bug watch added: Github Issue Tracker for ZFS #326 https://github.com/zfsonlinux/zfs/issues/326 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1847105 Title: very slow disk creation, snapshotting To manage notifications about this bug go to: https://bugs.launchpad.net/virt-manager/+bug/1847105/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
