Why I need a BDC?

Good question, and one that is almost always a "Yes."

A BDC is a great way to implement a network level fault tolerance. It will allow all your users to authenticate and access any shared resources in the event that your PDC goes down for whatever reason.

It also allows for maintenance to be performed on the PDC without bringing down your Windows network.

I may also lessen the load on the PDC because some users will authenticate off the BDC when the PDC is busy, unavailable, or happens to reply later than the BDC.

Lots more reasons why you should have at least 1 BDC, but running out of character space.

Yes.

1. If you do not have one, if your PDC goes down, nobody on your network can log in, or access resources on the network.

2. The BDC keeps a full copy of the security information for your network. Without it, if your PDC had a disk problem, you would have to fix/replace the drive(s), reinstall NT, then restore the registry from tape. Your network is down during this time. If for some reason you could not recover the registry from tape, you would have to recreate all accounts, and recreate all permissions on the server, since the new accounts would have different SID's than the old ones. If you also have Exchange it gets worse and you might also lose mailboxes.

Good luck.

As stated above s BDC is used for network fault tolerance, but you can utilize it for other duties which will remove some workload off of your PDC. The more tings oyu run on the PDC the larger the chance for problems. Use your BDC for tape backups or AT script scheduling. This will open the processor on the PDC and reduce the chance of downtime.

You bet.

Just imagine the situation where you build your PDC, it is working fine, no problems, no errors, you configure your users lets say 100 of them, could be even more, and sudently your PDC crashes, a hard disk failure, so your whole networkis down, and you're trying to figure it what happend, meanwhile nobody can login, you're getting phone calls from your user, your manager calls you and tells you I need this running in 2 minutes, there is no way a technician can fix this problem than quick.
Well if you have a BDC, which it can be a small machine, if the PDC goes down the PDC will automaticaly will let users to login just like if anything happended. You can promote the BDC as PDC and keep working, then you will have time enoughto fix your PDC problem.
To configure a BDC is not a big problem, it is very easy and a lot of time saver.
take my advice and do it, because sooner or later you will need it.

Good luck,

@lberto

If you have a bdc it will take some overhead off the pdc as far as authentication but what about everything else? the awnswer is do one better and try clustering with your pdc.

This question was closed by the author