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I have a server running RHEL6 with two NICs, each connect to separate switch. Two Cisco 3560 switches connected with a trunk link. The problem is the bonding link is not stable (lost some packets). When I unplug cable from 1 uplink from server to switch, many packets had been lost (about 50%). I've tried with all of Redhat bonding mode but cannot solve my problem. My question is: Can I do it and how?

Thanks in advance, giobuon

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You unplugged the cable between the switches? If that's the case, that would certainly cause the packets sent to the now-isolated switch to be lost - what behavior are you looking to achieve? – Shane Madden Feb 16 '12 at 5:46
Are you sure you want bonding? If you want to be able to continue to connect to systems connected to either switch, then you probably need to bridge your interfaces, and have spanning tree running. – Zoredache Feb 16 '12 at 7:22
ShaneMadden: It's uplink failure, I've edited my question to make thing more detail. @Zoredache: Where do I need to run STP? My switches only or both switches and server? TIA. – Gk. Feb 16 '12 at 10:53

I do this very thing.. In your modprobe.conf (if your using redhat 6) do you use Mode 6, and what do you set your miimon to? I set mine to 80ms..

I like mode 6, it makes things just work... Less throughput, but easy to survive a switch failover (also, with some of the 'fancy' modes, we couldn't do it to two seperate dell switches, even in a virtual chassis.)

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What he is describing isn't a switch failure though. It is a failure of an up-stream link. I don't see how any bonding mode will be useful for this. – Zoredache Feb 16 '12 at 7:21
I'm using mode 6 so far. The problem is still remain. If it is impossible, how do you guys deal with single point of failure on cable of uplink? – Gk. Feb 16 '12 at 11:08

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