Colo4Dallas Outage lesson

fteixeira

Member
Hello Guys,

After Colo4Dallas issue, I start to plan implement some changes for some important clients that I have.

I am planning to have a REAL REDUNDANCY for some websites of most importants clients. And I think that is possible to do it here along with KH since there are two different DC (TX and CA).

But I have some doubt about HOW to implement REAL REDUNDANCY and I would like to change ideas with someone interested in sharing information about that.

What is my idea:

1. To have 2 servers (on in TX other in CA) both with the same static site running;

2. To configure nameservers for my domains in registrar as:

ns1.domain.com point to server 01
ns2.domain.com point to server 02
ns3.domain.com point to server 01
ns4.domain.com point to server 02

Well here the doubts:

1. when both servers running fine, and I type my domains in my browser, where my browser will load the site? Ever In server 01? Or sometimes server 01 and sometimes server 02??? (I think that the reply is server 1, but I am not sure)

2. If server 01 fail, my browser will load the site automatically in server 02?

Any comments or suggestion???

:)
 

KH-Paul

CTO
Staff member
1. when both servers running fine, and I type my domains in my browser, where my browser will load the site? Ever In server 01? Or sometimes server 01 and sometimes server 02??? (I think that the reply is server 1, but I am not sure)
If you do #2 you'll end up accessing server1 50% of the time and in 50% of time you'll hit server2.

2. If server 01 fail, my browser will load the site automatically in server 02?
Nope, you'll continue to hits splitting between server1 and server2.

Any comments or suggestion???

:)
To get such things going content needs to be mirrored across two systems (not a bit deal with static content) and some sort of external monitoring and DNS management tools (either manual or automated) needs to be used to either switch nameservers or "A" records in DNS zones. Also, it is important to keep TTL low in zones for the domains that might need to be switched between servers.
 

fteixeira

Member
Well, seems that is not too simple as I had in mind. :(

I will need learning more about that. If someone more wish share experiences about that... is welcome.

Thanks
 

fteixeira

Member
Also, it is important to keep TTL low in zones for the domains that might need to be switched between servers.
Thanks you Paul for reply,

I am trying to learn about DNS failover. May it can help me, i dont know yet.

Can I configure TTL for 5 seconds?? This will cause overload on my VPS? Dns server (named) support TTL as 5 seconds? ISP will respect my TTL of 5 seconds or I continue have DNS caches issues?
 

KH-Paul

CTO
Staff member
Can I configure TTL for 5 seconds?? This will cause overload on my VPS? Dns server (named) support TTL as 5 seconds? ISP will respect my TTL of 5 seconds or I continue have DNS caches issues?
5 seconds is a bit on a low side. 300-600+ seconds might be a good value to start with as this will prevent tons of unnecessary DNS requests and yet won't let records be locally cached for long.
 
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