I found the cause of the problem. The tap interface of a instance has small tx length 500 packets. At a high network load (15-25 Kpps) and high CPU load on a guest some times queue overflows and the tap interface start drop network packages. I think that queue overflow occurs in moments of micro friezes (<1000ms) of a virtual machine. I solved this problem by increasing the tx_queue up to 10000.
-- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to qemu in Ubuntu. https://bugs.launchpad.net/bugs/1423631 Title: tap interface drops many packets on highload systems To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1423631/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
