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Replication frequency over line speed

By Susie1 ·
Does anyone know if there is a recommendation on determing the replication frequency for a Windows 2000 network given the network line speed?

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Things to consider

by timwalsh In reply to Replication frequency ove ...

I'm assuming we are talking AD replication.

You will not find anything published by Microsoft that will say "For a dial-up connection, replicate x times daily."

Things to consider when deciding on replication frequency:

How often do you change AD objects?
What is the size of your AD organization (i.e. how many other servers are you replicating to)?
What is your network bandwidth (if your replication is totally internal) or what type of connection do you have to the Internet (if your AD domain is part of a larger multi-site AD organization)?

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Yes AD replication

by Susie1 In reply to Things to consider

Lord, this is overwhelming.
Global network with over 12,000 nodes in the North American domain alone.
56 sites with all sites bridged.
Open replication schedule 24/7.
All types of connectivity from T3 to 56KB

We are currently using 60 minutes in general and 15 minutes for a T1 and up.
Is there any tool that I can use to determine the amount of data being replicated?

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by timwalsh In reply to Yes AD replication

Her is a bottom line before we go any further: With your current replication schedule, are you experiencing any bandwidth issues on any of your links? If the answer is no, then any of the following is really academic.

It may be of use if you are interested in truly optimizing your network, or if you begin havining problems in the future.

Replication only takes place between domain controllers, not between all nodes.

Intra-site replication takes place automatically and frequently. You don't have any control over this replication.

Inter-site replication is where you can designate the frequency of replication.

I really haven't found any MAGIC numbers to help determine an efficient replication frequency for a given link. Idid find an MS KB article that will allow you to somewhat accurately determin how long a given replication cycle may take. Take a look at MS KB Article Q244368 - How to Optimize Active Directory Replication in a Large Network.

MY gut feeling is that you are replicating too often. Another gut feeling is that you have too many replication links (because you are bridging all sites).

Unless AD objects are in a constant state of flux, you can start by changing the frequency. You need todecide what type of trade-offs you can make between having having accurate up-to-date information across your entire network and the cost in bandwidth of doing so.

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Replication (Cont.)

by timwalsh In reply to Yes AD replication

I would recommend trying the following replication topology (or something similar):

Since you have a global network, it makes little sense to replicate all sites on the same schedule unless all sites are running on a 24-hour schedule. It doesn't make much sense for a DC in a site in LA to be replicating with a DC in a site in Moscow when there is a 12-hour time difference. There will likely never be users in both offices (and thus the possibility of change being replicated) at the same time. Try this: create a bridgehead server in each large geographic area (or maybe several depending on number of time zones spanned). Have all sites within the geographic area replicate to the bridgehead server (but not with each other) on a frequent basis (every couple or 3 hours). Have bridgehead servers replicate with each other on a less frequent basis (depending on what if any overlap there is between working hours). For example, you need only replicate between LA and Moscow once or twice a day in order for each site to have an accurate picture of the other site.

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Thank you

by Susie1 In reply to Replication (Cont.)

Yes, we are experiencing some latency issues with inter-site replication. All sites are on a 24 hour schedule.

I am not concernced with intra-site. We have bridgehead servers in place.
We allow KCC to determine the replication topology.

I already have the Microsoft article. I was hoping that there was something more definitive out there.

Thank you for your help, I appreciate it.

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