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Skuba_85554's avatar
Skuba_85554
Icon for Nimbostratus rankNimbostratus
Nov 10, 2008

3dns/gtm and ltm question

hi

 

 

sorry if this question sounds a little basic... i have actually been on the gtm v9x training course back in june but this is my first attempt at a basic gtm config and i would appreciate any tips and advice on best practice etc if possible...

 

 

we have 2 datacentres with a v9 ltm in each which we use for load balancing our web sites. my manager wants a solution whereby we can 'flick a switch' and all traffic will be diverted to a basic web page at the other datacentre in case of emergency i.e. a basic message informing users we have a problem and we're working on it

 

 

DATACENTRE 1

 

contains a ltm unit and our main web services

 

(this will be where we would like the switch to be)

 

 

DATACENTRE 2

 

contains an ltm and a 3dns

 

 

DATACENTRE 3

 

an old datacentre which we no longer host any services at, but it does contain a 3dns only

 

 

all datacentres have good links between them

 

 

as you can see, although the end goal appears to be quite simple, the setup is a bit more tricky because we only have 3dns units and they're not located in the same datacentres as the ltm units

 

 

does anyone have any opinions on the best way to go?

 

 

thanks
config
design
  • dennypayne's avatar
    dennypayne
    Icon for Employee rankEmployee
    Nov 10, 2008
    I'm not totally clear on whether you have 3-DNS (v4) or GTM (v9), but in either case the same principle should work, if you have the 2 GTM's in a sync group, and they are monitoring the 2 LTM's, they should be able to use the Global Availability metric in a standard config to have DC1 as the primary LTM and DC2 as the backup. You wouldn't have to "flick a switch", GTM just begins handing out DC2 LTM addresses if the LTM in DC1 fails.

     

     

    It doesn't matter where the devices are as long as they are able to monitor the LTM's on their public-facing interfaces (using iQuery on port 4353 as well as ssh-22 and https-443).

     

     

    Denny
  • Skuba_85554's avatar
    Skuba_85554
    Icon for Nimbostratus rankNimbostratus
    Nov 11, 2008
    hi denny - thanks for your reply

     

     

    in answer to your questions:

     

    - we don't actually have any gtm's in place at the moment. just 2 3dns units

     

    - we require the ability to perform a manual failover rather than it being automatic

     

     

    basically, all we're trying to achieve is a mechanism to push a button which fails over our web sites (hosted in datacentre 1) to a maintenance page (in datacentre 2) explaining that we are experiencing technical difficulties

     

     

    one idea was to make use of the manual resume option. if you had your maintenance page as the primary resource and your web sites as the secondary resource but ensure the primary has failed over to the secondary! then use manual resume to fail back on to the primary (which is actually the maintenance page)

     

     

    hope that makes sense!

     

     

    i'm going to try and get an eval licence for gtm so i can play around with the configs on our test platform. at the minute, i'm working from memory which is very difficult