[quagga-dev 3482] Re: [PATCH] non-blocking I/O from client daemonstozebra

Simon Talbot simont at nse.co.uk
Fri Jun 3 09:24:51 BST 2005

>Having additional test boxes really helps. Also, one of the advantages
of Quagga is that you should have saved enough money >to be able to
install a second router. With the trend towards ethernet interconnects
that can be more easily shared without >fancy hardware (compared to

The routers in question are already a cluster, two identical hardware
units using Linux-HA techniques for failover. With the work queues
installed, both behaved in exactly the same way and kernel panicked,
once rolled back to a know good version they were fine. They are routers
of which we have about 20 throughout the business, all running the exact
same kernel build (our own custom wrapping of 2.4.22) and are (touch
wood) extremely stable -- I cannot remember the last time any of them
ever re-booted or kernel panicked. To make two of them, both behave in
the same way (kernel panic) with a software version change and then
behave properly again when the version id rolled back would definitely
lead me to the software as the root cause -- even if it is actually
memory starvation which is causing the panic.

The routers are both 512MB Ram with no swap disk -- well they have no
disk at all -- so when they run out of RAM, they really run out !

The following is the memory stats of one of the routers, when stable
running 0.99.0

             total       used       free     shared    buffers
Mem:        506296     255988     250308          0        336
-/+ buffers/cache:     171280     335016
Swap:            0          0          0

I have more of these routers, but I think the fault is load related,
which makes it very tough to re-create outside of the production
environment due to the large number of peers etc.

I will put my brain to possible wait to test this, but unfortunately
logging is carried out to RAM disk, so once the routers kernel panic and
then re-boot (by the watchdog) the evidence has gone !

If you have any thoughts as to how/what I can do to diagnose this
further, please let mw know,


Paul Jakma	paul at clubi.ie	paul at jakma.org	Key ID: 64A2FF6A
The secret of healthy hitchhiking is to eat junk food.

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