[Linux-HA] heartbeat with only 1 NIC per server?
max.hofer at apus.co.at
Mon Jul 23 04:03:23 MDT 2007
HA is about redundancy. This means having 1 NIC will
probably not make you system very reliable.
Does the NIC have 2 ports?
Your worst case scenario (as I can think of):
- connection failures to one of the NICs (!not NIC failure)
which will turn off/on/off connectivity (this may be cabling
problems, switch problems etc.)
---> your cluster will split, rejoin, split rejoin. And I'm sure
it will not take long and you have a split brain problem.
Back to your question:
- we run heartbeat over the LAN, not a big problem if you use
it only to share heartbeat data (i.e. no big data is transferred
like DRBD devices etc.).
Your problem is that you do not have connection redudancy
between the cluster nodes.
Possible solution: what about interconnecting the two servers
with a serial cable? At least you will avoid the split brain problem
when the network fails.
WHat about USB connections?
kind regards Max
On Monday 23 July 2007, Rudi Ahlers wrote:
> Hi all
> I hope someone can assist me with this one. I previously (almost a year
> ago) setup heartbeat on 2x Suse 9.3 machines, where each server had a
> wireless NIC & a onboard NIC. The network ran on the wireless NIC's, and
> I then used the onboard NIC's with a crossover cable to monitor heartbeat.
> Recently, we took out the wireless network, and put in a 8 port 10/100
> switch to run eveything on. So, each server now only has 1 NIC. The
> wireless gave us too many problems, and getting working cards was a
> problem. To put it differently, the client is 700KM away, and not IT
> literate, so we had to fedex the wireless NIC to them, and try and make
> it work over the phone. Bottomline, running a normal CAT5 LAN is less
> error prone.
> So, to get back to the question. How stable / safe / redundant is it to
> run heartbeat over the same NIC's as the LAN?
> If server 1 use IP 192.168.0.5, server 2 use 192.168.0.6 & tell
> heartbeat to server 192.168.0.3 on the LAN, will this work well enough?
More information about the Linux-HA