Linux route caching and busy Bird protocols

[Ondrej Zajicek]

On Fri, Jul 13, 2012 at 01:26:03AM -0500, Michael Vallaly wrote:
> 
> Hello again fellow bird users,
> 
> Not sure if anyone has run across this before or not, but poking around
> with a couple of bird (1.3.7 and 1.3.3) instances on Linux (2.6 - 3.3),
> it seems that something related to bird is flushing the kernel route
> cache _very_ frequently?
> 
> So quickly in fact that I often don't have _ANY_ cached routes
> displayed when running bird (BGP protocol ~400k routes). I noticed this
> initially running a simple 'watch -n 1 ip route show cache'.
> 
> Is this normal? As soon as I disable the BGP protocols in bird I start
> seeing expected cached routes populate for connected networks,
> that persist normally for while till they eventually timeout.

I don't know. I would guess that any change in routing table
may invalidate route cache, and that is internal kernel
implementation issue. But even in that case there would be probably
many new cached entries between route changes. So i would guess
it is iproute2 issue (or kernel not sending notifications about
cache entries) but not really problem with caching.

-- 
Elen sila lumenn' omentielvo

Ondrej 'SanTiago' Zajicek (email: santiago at crfreenet.org)
OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net)
"To err is human -- to blame it on a computer is even more so."
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 197 bytes
Desc: Digital signature
URL: <http://trubka.network.cz/pipermail/bird-users/attachments/20120723/031d44df/attachment-0001.asc>