Date: Mon, 26 May 2008 00:51:00 GMT From: Barrett Lyon <blyon@blyon.com> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/123991: ECMP balancing issues Message-ID: <200805260051.m4Q0p0IY095865@www.freebsd.org> Resent-Message-ID: <200805260100.m4Q108Hu090276@freefall.freebsd.org>
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>Number: 123991 >Category: kern >Synopsis: ECMP balancing issues >Confidential: no >Severity: non-critical >Priority: low >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Mon May 26 01:00:08 UTC 2008 >Closed-Date: >Last-Modified: >Originator: Barrett Lyon >Release: 8.0-CURRENT >Organization: >Environment: FreeBSD home.blyon.com 8.0-CURRENT FreeBSD 8.0-CURRENT #3: Sun May 25 02:18:13 PDT 2008 blyon@home.blyon.com:/usr/obj/usr/src/sys/GENERIC i386 CVSUP as of May 25th >Description: Using RADIX_MPATH support in the kernel provides the desired ECMP support, however ECMP does not appear to load balance properly. The first route appears to be a primary route, were the second path becomes almost a backup route. Removing the first and re-adding it causes the preference to swap. This is also seen in the netstat -rn "Use" output, where the counter on the => route is always higher than the secondary route. The destination IPs are very mixed. The desired effect would be a better load distribution across the two next-hops or even per-packet load balancing as an option. >How-To-Repeat: Add two routes with different next-hops, the first route becomes the preference route. >Fix: none >Release-Note: >Audit-Trail: >Unformatted:
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