From: Thomas Graf <tgraf@infradead.org>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Simon Chen <simonchennj@gmail.com>, netdev@vger.kernel.org
Subject: Re: increase the number of routing tables
Date: Mon, 30 Jan 2012 07:25:46 -0500 [thread overview]
Message-ID: <20120130122546.GE8376@canuck.infradead.org> (raw)
In-Reply-To: <1327804887.2805.20.camel@edumazet-laptop>
On Sun, Jan 29, 2012 at 03:41:27AM +0100, Eric Dumazet wrote:
> Le samedi 28 janvier 2012 à 21:20 -0500, Simon Chen a écrit :
> > Hey folks,
> >
> > To my limited knowledge, Linux currently supports 256 (255?) routing
> > tables defined in /etc/iproute2/rt_tables.
> >
> > Is there a way to increase this number to something much larger? Are
> > there performance/scalability concerns there? I am trying to have
> > customized routing table for each IP address (using "ip rule add from
> > xxx table yyy"). I am not sure exactly how many IPs I'll handle, but
> > certainly more than 255...
> >
>
> Its is possible, but probably not scalable.
>
> You really should not have too many "ip rule" entries, since they are
> evaluated linearly.
>
> The limit being ~32768 rules
>
> # ip rule
> 0: from all lookup local
> 32763: from all to 1.2.3.7 lookup test3000
> 32766: from all lookup main
> 32767: from all lookup default
I've run into these scalability issues a while ago which is
why I've added the goto action allowing to build a tree like
structures:
0: from all lookup local
10: from eth0 goto 4000
[possibly thousands of rules]
3999: from all goto 32763
4000: from all to 1.1.1.1 lookup foo
[...]
32763: from all to 1.2.3.7 lookup test3000
32766: from all lookup main
32767: from all lookup default
next prev parent reply other threads:[~2012-01-30 12:25 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-29 2:20 increase the number of routing tables Simon Chen
2012-01-29 2:41 ` Eric Dumazet
2012-01-29 2:46 ` Ben Greear
2012-01-29 4:20 ` Simon Chen
2012-01-29 19:26 ` Ben Greear
2012-01-31 3:06 ` Simon Chen
2012-01-29 21:02 ` David Miller
2012-01-29 21:01 ` David Miller
2012-01-30 17:26 ` Ben Greear
2012-01-30 17:36 ` David Miller
2012-01-30 12:25 ` Thomas Graf [this message]
2012-01-30 12:44 ` Eric Dumazet
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