Failover for business continuity
ram at netcore.co.in
Wed May 30 09:53:57 EDT 2012
On 05/30/2012 02:26 PM, Eric Luyten wrote:
> On Wed, May 30, 2012 9:24 am, Ram wrote:
>> On 05/30/2012 12:43 PM, Dmitry Banschikov wrote:
>>> On 05/30/2012 10:52 AM, Ram wrote:
>>>> I am trying to setup a remote cyrus-replica to a different geographical
>>>> location for business continuity.
>>>> In case the main server goes down the users will get switched to the
>>>> remote server by making a DNS change. The only issue is DNS replication
>>>> would take a long time so the switch is not instantaneous. How would one
>>>> make the switch instantaneous ? Moving the IP is not possible because the
>>>> Remote server is on a different network
>>> You can set TTL of RR to very small value (say 60 seconds). In this
>>> case, DNS change will be propagated fast.
>> But I have seen some DNS clients , especially on windows , do not honor
>> For a 10 minute TTL , even after 4 hours the windows server keeps
>> resolving to the old server
> Some OSes/applications/resolver libraries will keep on using the 'old'
> values until *they* see fit.
> DNS-based failover is (and always has been) a very low cost, halfbaked
> solution. Been there, done that...
So if not DNS based fail over , what is the other alternative.
I cant move the IP , or re-announce BGP
I cant have both servers in active-active mode
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