Hi Joe, If you want to use a true link aggregation protocol such as LACP or Cisco's Etherchannel, you'll need an L3 switch that supports the protocol as well (and a Cisco switch at that, in the case of Etherchannel). Both partners in a link aggregate must be aware of the aggregate, and ports that are not part of the aggregate cannot be connected to it, and vice-versa (although typically a switch will simply stop forwarding if they detect agg links on non-agg ports, or non-agg links on agg ports).
In the case of ALB, the uplink switch does not need to be made aware that there's an aggregate, since the kernel that manages the aggregate will transparently remap everything. The switch will simply notice that a given IP is now associated with a new MAC address and update its ARP cache. This can noisy in switch logs, but on a dumb switch, nobody's the wiser. My gut tells me this works, even with a dumb switch. The only way to know for sure, though, is simply to test it out yourself. I would try it out with a pair of dumb switches connected together rather than putting it directly on your network. If STP is active, plugging in this configuration may shut down your whole network if STP thinks it found a loop, so test it out in a sandbox before you go live. hth, Klaus -----Original Message----- From: [EMAIL PROTECTED] on behalf of Joe Georger Sent: Wed 10/22/2008 5:00 AM To: [email protected] Subject: Re: [Lustre-discuss] Lnet configuration: 1 ost per gige interface. Even for bonding mode 6? * balance-alb or 6 Adaptive load balancing: includes balance-tlb plus receive load balancing (rlb) for IPV4 traffic, and does not require any special switch support. The receive load balancing is achieved by ARP negotiation. The bonding driver intercepts the ARP Replies sent by the local system on their way out and overwrites the source hardware address with the unique hardware address of one of the slaves in the bond such that different peers use different hardware addresses for the server. Receive traffic from connections created by the server is also balanced. When the local system sends an ARP Request the bonding driver copies and saves the peer's IP information from the ARP packet. When the ARP Reply arrives from the peer, its hardware address is retrieved and the bonding driver initiates an ARP reply to this peer assigning it to one of the slaves in the bond. A problematic outcome of using ARP negotiation for balancing is that each time that an ARP request is broadcast it uses the hardware address of the bond. Hence, peers learn the hardware address of the bond and the balancing of receive traffic collapses to the current slave. This is handled by sending updates (ARP Replies) to all the peers with their individually assigned hardware address such that the traffic is redistributed. Receive traffic is also redistributed when a new slave is added to the bond and when an inactive slave is re-activated. The receive load is distributed sequentially (round robin) among the group of highest speed slaves in the bond. When a link is reconnected or a new slave joins the bond the receive traffic is redistributed among all active slaves in the bond by initiating ARP Replies with the selected mac address to each of the clients. The updelay parameter (detailed below) must be set to a value equal or greater than the switch's forwarding delay so that the ARP Replies sent to the peers will not be blocked by the switch. * Prerequisites: 1. Ethtool support in the base drivers for retrieving the speed of each slave. 2. Base driver support for setting the hardware address of a device while it is open. This is required so that there will always be one slave in the team using the bond hardware address (the curr_active_slave) while having a unique hardware address for each slave in the bond. If the curr_active_slave fails its hardware address is swapped with the new curr_active_slave that was chosen. Brian J. Murrell wrote: > On Tue, 2008-10-21 at 12:15 -0500, Hendelman, Rob wrote: > >> I was under the impression that bonding nics required a manged switch to >> support this. >> > > It does require a switch that supports link aggregation yes. Sorry, I > overlooked that you only had a dumb switch. > > b. > > _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
