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2 Apache web servers with identical vhosts to serve a few hundred clients. RHEL 6 on all boxes. What are the pros and cons to having a load balancer with a VIP, and pointing all of the DNS A records to the VIP vs having no load balancer in front and just using 2 A records for each site, one with server A IP, and the other with server B.

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closed as primarily opinion-based by Wesley, Sven, Jenny D, Dave M, Ladadadada May 4 at 20:12

Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise.If this question can be reworded to fit the rules in the help center, please edit the question.

    

3 Answers 3

Pro for dedicated load balancer:
It actually can balance the load (depends on the software of course).
You can disable a backend node without anyone noticing it.
If a node crashes only the current connection dies (if at all) and the next request from the same client goes to a different node (vs. the client caches DNS and hits it again and again).

Pro for DNS round robin?
I don't know. It's cheap I guess.

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@faker has a good answer. i would comment to that, but my rep does not allow. a couple of additional pros for each:

load balancer

  • can reliably scale (dns cache can delay RR scaling)
  • in most cases, you can have a heterogenous cluster with machines of different capabilities - with RR, you are only as strong as your weakest link

RR

  • likely marginally faster, since there's less routing
  • one less point of failure (less true if you are using a managed lb like AWS ELB)
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Pros of RR dns:

  • cheap
  • easy

Cons of RR dns:

  • in case of host failure, you loose all the traffic while restoring it (or at least the time of dns propagation for a new ip)
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