From: Pavel Bykov (slidersv@gmail.com)
Date: Sun Feb 15 2009 - 20:39:31 ARST
Just a couple of pointers from the experience and from the top of my head:
1. You have to think in both directions and it will really depend on what
you're failing over. If you have two sites with geographical server cluster,
all you'll need is routing protocol convergence. Otherwise you might look
into GSS. But with separate sites that are not balanced on application level
where you would use DNS solution, it will not be "seamless" because of all
the caches. What you could do is "anycast" by blocking/tracking
availability, and in case of problems brining up same IPs in different
location. But there are other implications to consider - like what if the
problems are between two sites? You'll then have two IP addresses active
basically balancing the traffic, which is not good unless servers are
interconnected on application level, which brings us back to application
cluster...
2. Uh, it really depends on the size, data criticality, server load etc.
Also it depends if you are going to sync databases directly or Storage
Systems. From experience 12 to 24 hours should be enough. But it really
depends...
3. ACE (descendad of CSS) usually load balances very close to servers,
therefore it's located close to server lan. It's purpuse is mostly to
balance load locally, while GSS's purpose is to balance load geographically.
It definitely could be used for failover as well, but for site failover to
another site, the uses are more limited.
On Thu, Feb 12, 2009 at 7:03 PM, Haroon <itguy.pro@gmail.com> wrote:
> Hello Experts,
>
> My question is somewhat off topic, I hope that is okay. I am trying to
> figure out how to setup site redundancy for online highschool and
> university
> setup, a backup site for our primary location so in case of power/equipment
> failure or ISP issues, the users are not effected by the down time.
>
>
> 1. In case of failure at the main site, the switch over should be
> seamless to the end user. I believe this is possible with DNS load
> balancing, any recommendations? Off site dns load balancer?
> 2. SQL databases should sync hourly or at least once a day for latest
> data at the backup site.What software would do this?
> 3. What type of equipment is required on each site to accomplish this
> setup? Cisco's CSS of any use here?
> 4. Do I need to get a dedicated site to site VPN?
>
>
> Any other suggestion or ideas would be greatly appreciated.
>
> Thank you,
>
> Haroon
>
>
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-- Pavel Bykov ---------------- Don't forget to help stopping the braindumps, use of which reduces value of your certifications. Sign the petition at http://www.stopbraindumps.com/Blogs and organic groups at http://www.ccie.net
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