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List:       linux-ha-dev
Subject:    [Linux-ha-dev] Re: Fwd: Re: Heartbeat issue
From:       Alan Robertson <alanr () unix ! sh>
Date:       2004-03-17 17:18:25
Message-ID: 40588861.2000409 () unix ! sh
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Philippe Bourcier wrote:
> 
> Re,
> 
>>> That's one step further...
>>> But, why not (simply) force by default the address specified as the 
>>> source...
>>> Since the configuration looks like "ucast eth0 10.0.0.1" ... forcing 
>>> 10.0.0.1 as a source address seems feasible.
>>
>>
>> But, it's not our address - we don't own it.  It belongs to the other 
>> node, the one we're trying to reach.  That seems suspicious at best.
> 
> 
> Oops, indeed... but we can know what is the real address of the 
> interface which should reach that other one.
> 
>> Just a thought...
>> How far apart are your buildings? Is there a line of sight between 
>> them? Did you ever think about replicating your land lines with a 
>> heartbeat link over wireless 802.11b? For a couple thousand $ USD you 
>> might be able to put in a 1-2 mbit wireless net connecting the two 
>> sites.  Then you would have reliable redundant heartbeat connections 
>> between the sites - because I think you could make it very unlikely 
>> that both your land line and your wireless net would go down at the 
>> same time.
> 
> 
> - 300-400 meters, but...
> For security reasons wireless is prohibited in our environment, but 
> that's a good idea to keep for some other client.
> Note that our land lines are two redundant fiber rings which goes 
> through different paths which is probably much better than what wireless 
> could offer...

OK.  At least you think it sounds like a generally sane idea ;-).  That's a 
plus ;-).  I've been wanting someone to try that and get back with a report 
on how it worked out.

As long as you know they go through different paths for every meter 
underground with some certainty.

That's often hard to verify once you bury your wires in the ground.  But 
for that distance, it should be possible.

My general rule (given no other input) is that once you bury your wires in 
the ground, I start getting nervous about single points of failure - 
because of the difficulty of doing this in general.


-- 
     Alan Robertson <alanr@unix.sh>

"Openness is the foundation and preservative of friendship...  Let me claim 
from you at all times your undisguised opinions." - William Wilberforce

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