Re: multiple network interfaces

[Mark Travis]

This contradicts a recommendation in the documentation, under section 16.3.1:

---
For enhanced reliability, you can use dual switches and dual cards to remove the network as a single point of failure; many device drivers support failover for such communication links.
---

My testing shows that dual NICs sharing a single IP through linux bonding works just find on data nodes--but I want to know why this is not recommended. The appliction (neither ndbd nor mysqld) does not have any idea that the primary connection failed--at the worst it will need to do a single TCP retransmission.

What's the reality?

Thanks!

Alex Davies wrote:
> * This post is an attempt to be helpful. I am not
> sure about any of it :) *
>
> > I don't understand this explanation. How
> can
> > there be a 'route open' to a dead node? And
> is
> > the 'confirmation that the node went down'
> simply
> > the loss of the TCP connection or something
> else?
>
> I think that this is only refering to situations
> where you have two ethernet connections in some
> kind of bonding or HA setup - if you have two
> different interfaces set to different IPs I know
> that this is a not a problem. If you have two
> interfaces bonded together what it is saying is
> that it does not like failing over - and as far as
> it is concerned the node is "dead" because the
> first network interface died (and therefore the
> connection that was going on was not completed)
> yet there is still a route open via the backup
> interface. MySQL cluster does not like that, so do
> that at your own risk!
>
> > b) tell me if there is any kind of
> workaround
>
> What are you trying to achieve?
>
> I can confirm that you *can* run a cluster just
> fine with multiple NICs as long as they are set to
> different IPs (typically a "private" and a
> "public" with the private on a reserved range such
> as 10.0.0.x or 192.168.x.x)
>
> If you want more network redundency then simply
> run more nodes. You could run two seperate NICs
> and have two storage nodes on that box - with each
> using a different NIC allowing you some fault
> tollerance.
>
> With best wishes,
>
> Alex
>
> >
> > Thanks,
> >
> > Rick
>



Edited 1 time(s). Last edit at 01/06/2006 06:33PM by Mark Travis.