Determine WAN link spee for 300 MB of replication per hour

Hi friends,

Our client has contracted us for implementation of a disaster recovery plan for their data center. The DR center is 500 km away from the data center and requires 300-400 MB of data to be replicated per hour. I am not sure what is the WAN link speed that I need for this?

I am also not sure if the replication is going to be a sync or an async copy. Is there any formula or practical speed that you recommend for this kind of replication? If there are any links that you can point out in such a setup, please let me know of the same.

THanks a lot Gautam

Reply to
gautamzone
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the distance is irrelevant for calculating the thruput you need (but has major implications for which protocol to use)

400 MB / hr = 400 * 8 bits * (overhead) / (60 min per hr) / (60 sec per min)

=400 * 8 * overhead / 3600 = less than 1 Mbps *overhead.

you usually want a fair amount of headroom - but 100% is a good starting point for now since you havent specified whether this is 400M at application level, or IP, whether it is lots of small transactions or a few big ones etc. - so a 2 Mbps line is my 1st guess.

however - you need to check if that is the peak rate needed. Often the link speed is dictated by the time needed to resync after a problem rather than steady state replication traffic.

Sync copy normally needs more bandwidth as any network / copy delay translates directly into lower performance for the application - so the limiting factor becomes low and predictable latency rather than bandwidth use.

You need a lot more info to define what is needed than just thruput, since you need to know effect on application, what is acceptable response time, transaction size, protocol overhead and probably a lot more.

So - the response is - ask the application provider what you can / have to do and then decide.

Reply to
stephen

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