From: "Robert Comer" 

I have a feeling that the IP address switching itself isn't a great way to
go.  I've never had an instance where I switched out IP addresses/machines
and everything just worked without the users noticing anything.

I believe there are third party failover products as well, but I don't have
any experience with them...

- Bob Comer


"Ellen K."  wrote in message
news:g9ar91ppgegcmsf59nq69v9sqc12j8jfl4{at}4ax.com...
> Well, then probably the "official" clustering solution is
the way to go.
> I haven't really delved into it yet but I did see that the IP addresses
> can be on different subnets.
>
> On Wed, 1 Jun 2005 04:19:33 -0400, "Robert Comer"
>  wrote in message :
>
>>>I am so ignorant about this stuff.  Would that still work if the servers
>>> are in different cities?   (I suspect my boss is going to want to have
>>> the redundancy between LA and TJ.)
>>
>>Routing is going to be a big problem if both servers are on different
>>subnets.  (a showstopper sized problem)
>>
>>- Bob Comer
>>
>>
>>"Ellen K."  wrote in message
>>news:8kfq9198bar3hr2okk4o98dfebpdqj7qf3{at}4ax.com...
>>>I am so ignorant about this stuff.  Would that still work if the servers
>>> are in different cities?   (I suspect my boss is going to want to have
>>> the redundancy between LA and TJ.)
>>>
>>> For that matter, if we went with clustering, would clustering work on
>>> servers in different cities?
>>>
>>> On Tue, 31 May 2005 08:36:15 -0400, Mike N.

>>> wrote in message :
>>>
>>>>On Mon, 30 May 2005 23:40:14 -0700, Ellen K.

>>>>wrote:
>>>>
>>>>> It did occur to me that since we have static routing
(I think), just
>>>>>assigning a new IP address might not be enough.  Is an
"ARP table"
>>>>>where
>>>>>the routing instructions live?  Would new instructions get added
>>>>>automatically?
>>>>
>>>>  The "ARP table" is the IP address - to -
Ethernet Hardware address
>>>>translation table that contains all ethernet hardware
addresses on your
>>>>LAN
>>>>segment.  It is created automatically by each host on TCP/IP as you
>>>>communicate with anything else.
>>>>
>>>>   One way to eliminate the user complexity of IP
switchover is to put a
>>>>'traffic director' device in front of the 2 servers.   The
device would
>>>>detect a timeout / lack of response from the primary and
automatically
>>>>switch to backup.   Normally these are used for web servers for
>>>>redundancy
>>>>to one or more web servers from a single IP.  They may
require a special
>>>>configuration or manual failover to work for SQL server in your
>>>>application.   But upon further thought - if you are using manual
>>>>failover,
>>>>the same thing would be accomplished by a simple router in
front of the
>>>>2
>>>>servers.
>>>
>>
>

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