I found a bug report upstream (Linux kernel) that has the same symptoms to your issue. May you review it, and if you believe this is the same problem you have, I can link the two reports:
"Large I/O operations result in poor interactive performance and high iowait times" https://bugzilla.kernel.org/show_bug.cgi?id=12309 ** Bug watch added: Linux Kernel Bug Tracker #12309 http://bugzilla.kernel.org/show_bug.cgi?id=12309 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/999386 Title: Disk access locking whole PC To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+bug/999386/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
