> I in fact have bonded interfaces on the laggy server. When I checked > the bonding config, I realized a while ago I had changed from > balance-rr / mode 0, to 802.3ad / mode 4. (I did this because I kept > getting "bond0: received packet with own address as source address" > when using balance-rr with a bridge interface. The bridge interface > was for using KVM.) See the comments about mode 0 in this thread, http://lists.centos.org/pipermail/centos-virt/2014-March/003720.html in particular http://lists.centos.org/pipermail/centos-virt/2014-March/003733.html > Like the Serverfault poster, I have an HP TrueCurve 1800-24g switch. > The switch is supposed to support 802.3ad link aggregation. It's not > a managed switch, so I (perhaps incorrectly) assumed that 802.3ad > would magically just work. Either there is more required to make it > work, or it's implementation is broken. Curiously, however, running > my bond0 in 802.3ad mode did work without any issue for over a month. I'm unfamiliar with these switches. The Cisco switches we use, all managed, require explicit configuration for LACP/802.3ad.