Authoritative restore

Joe · Aug 4, 2004

Am i right with this?

I have 2 DCs currently online (say Server "A" and
Server "B"), one of them is having problems replicating
and has its AD database corrupted. So...i'm planning an
authoritative restore from Server A to Server B (again,
Server "B" has its AD corrupted). These are the steps for
an authoritive restore?

1.Run NTDSUTIL from Server "A"
2.type authoritative restore
3.type restore database

OR

1.Reboot Server "A" and enter in Service Rest. Mode
2.Run NTDSUTIL from Server "A"
3.type authoritative restore
4.type restore database
5.Quit and restart

Joe · Aug 4, 2004

Thanks a lot...

Just one more question.

Unfortunatly (my mistake, i know) i have no system state
neither AD backup. So, i guess what i have to do is the
non-authoritave restore/process (on Server "B") skiping
the restoring step, right? I hope this help, otherwise, i
think my last option is demote and promote Server "B".

-----Original Message-----
Hi,

In your case, you must do a NON authoritative restore on

your server B with a backup of server B. You boot in AD
restore mode and restore system state of server B then you
reboot normally the server.

When it will come online, it will replicate data from your server A.

What is an authoritative restore?

You have to do an authoritative restore when you have

deleted something in AD that you should not and the DC on
which you delete rthe object has replicated with other DC.
Now the deleted object is referenced in AD as deleted.

Each object in AD has a USN which is the version of the object.

To restore your deleted object you boot in AD restore

mode, you restore system state. Your deleted object is now
restored but its USN is smaller than the USN of the
deleted object that is curently in AD. So when you reboot
your dc, it replicates with other, the USN of the deleted
object is greater than the restored object so it deletes
it.

In order to make the USN of the restored object greater

than the deleted object, you use authoritative restore but
only on your deleted object. It will add 100 000 to the
USN of the restored object. So when replcate, it will be
kept.

ptwilliams · Aug 4, 2004

Is demoting and promoting that big a deal?? Without a backup I wouldn't
hesitate to do just that...

--

Paul Williams
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Thanks a lot...

Just one more question.

Unfortunatly (my mistake, i know) i have no system state
neither AD backup. So, i guess what i have to do is the
non-authoritave restore/process (on Server "B") skiping
the restoring step, right? I hope this help, otherwise, i
think my last option is demote and promote Server "B".