Re: Global Catalog size

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From: Eshprof (Eshprof_at_discussions.microsoft.com)
Date: 01/13/05 

Date: Thu, 13 Jan 2005 12:05:03 -0800

Thanks for your input so far. As I stated before, you have been a lot of help.

How would I find out the size of the domain partition on the other GCs in
the other domain? Or for that matter how do I found out the size of it in
general?

"Mike Brannigan [MSFT]" wrote:

> "Eshprof" <Eshprof@discussions.microsoft.com> wrote in message
> news:913FA3E6-B52F-4CE4-80B0-DBD5E308A353@microsoft.com...
> > Thank you!!!
> >
> > Do all CG servers do the initial recreation from their own domain
> > partition
> > and then just re-synch the changes to their partners?
>
> A GC already has its own domain partition so does not need to do anything
> about that beyond it usual replication with its partners.
> It then finds the other DCs from the other domains and replicates in from
> them the partial attribute sets for al objects in each of those domains
> until it has a complete Global Catalog.
>
> > Is that what is meant
> > by a full re-synch or do they send to their partner an entire copy of the
> > catalog?
>
> The catalog is built from the other DCs in the other domains sending the GC
> the domain partition (partial attribute set of thier domains).
>
> > I think that's the missing piece for me. With the ntds.dit file of
> > 8.6GB that's a huge catalog to send in it's entirety. I can't fathom what
> > that would do to our network.
> >
>
> If you are using 2000 for your DCs and GCs you will always have this risk,
> upgrade to 2003 on DCs and GCs and you remove this nightmare scenario.
>
> > I guess my thought process is when I think of running DCPromo on a 2000 or
> > a
> > 2003 server. The server is going to get a full copy of AD.
>
> From another Dc in the same domain yes,
>
> > From then on, it
> > is going to replicate only the updates/changes. So with the GC, does it
> > get
> > its "full copy" from the Directory Partition on it's on machine and then
> > replicate/synch the changes without sending the entire file to it
> > partners?
> >
>
> So the GC (which is a Dc in its own domain already has that information for
> its own domain and then in the initial (or full synch scenarios) get a copy
> of every object and only the GC partial attributes from another DC in a
> different domain. It does this until it has all the domain in the forest in
> its GC.
>
> > What tools beyond replmon would you suggest for testing?
> >
>
> There is a great article on trouble shooting AD replication at
> Troubleshooting replication
> http://www.microsoft.com/resources/documentation/WindowsServ/2003/standard/proddocs/en-us/Default.asp?url=/resources/documentation/windowsserv/2003/standard/proddocs/en-us/sag_adsite_trouble_1.asp
> >
> > You have been a tremendous help!
> >
>
> Your welcome.
>
> --
>
> Regards,
>
> Mike
> --
> Mike Brannigan [Microsoft]
>
> This posting is provided "AS IS" with no warranties, and confers no
> rights
>
> Please note I cannot respond to e-mailed questions, please use these
> newsgroups
>
> "Eshprof" <Eshprof@discussions.microsoft.com> wrote in message
> news:913FA3E6-B52F-4CE4-80B0-DBD5E308A353@microsoft.com...
> > Thank you!!!
> >
> > Do all CG servers do the initial recreation from their own domain
> > partition
> > and then just re-synch the changes to their partners? Is that what is
> > meant
> > by a full re-synch or do they send to their partner an entire copy of the
> > catalog? I think that's the missing piece for me. With the ntds.dit file
> > of
> > 8.6GB that's a huge catalog to send in it's entirety. I can't fathom what
> > that would do to our network.
> >
> > I guess my thought process is when I think of running DCPromo on a 2000 or
> > a
> > 2003 server. The server is going to get a full copy of AD. From then on,
> > it
> > is going to replicate only the updates/changes. So with the GC, does it
> > get
> > its "full copy" from the Directory Partition on it's on machine and then
> > replicate/synch the changes without sending the entire file to it
> > partners?
> >
> > What tools beyond replmon would you suggest for testing?
> >
> >
> > You have been a tremendous help!
> >
> > Thank you.
> >
> > "Mike Brannigan [MSFT]" wrote:
> >
> >> "Eshprof" <Eshprof@discussions.microsoft.com> wrote in message
> >> news:5A570124-0F25-46DD-84B4-2C629BC43E53@microsoft.com...
> >> > Thank you. Let me add a few more questions for clarification:
> >> >
> >> > I read from the "Windows 2000 Active Directory Black Book" that when
> >> > there
> >> > is a re-synch, the current GC information is discarded and rebuilt from
> >> > scratch.
> >> >
> >> > 1.If the GC information is discarded and rebuilt, then with what
> >> > machine
> >> > does it start? Is that accurate information or does a GC just contact
> >> > the
> >> > other GCs to make sure they are "all on the same page"?
> >> >
> >>
> >> The information in the partial attribute sets for all the Domains in the
> >> forest that the GC is holding a copy of are deleted and new data
> >> gathered.
> >> All the information is requested again from its partners hence the
> >> potential
> >> for a huge volume of on wire network traffic.
> >>
> >> > 2. Does it truly discard the data and start afresh? Discarding the
> >> > data
> >> > concerns me, because our ntds.dit file is approximately 8.6GB. Would
> >> > all
> >> > 8.6GB be replicated or just the changes, and then the GCs just confirm
> >> > they
> >> > are all in synch? Which GC is the base-line?
> >> >
> >>
> >> Yes as above all information is replicated to the GC as required for all
> >> the
> >> other Domain partitions in the forest.
> >> There is no base line a GC is a DC for a Domain so is authoritative for
> >> that
> >> Domain information - by default it will contact other DCs in the other
> >> domains to get the partial attribute set of all objects in that domain
> >> from
> >> that DC.
> >>
> >> > 3. Thank you so much for your answers. I am though, not quite grasping
> >> > your
> >> > answer "The GCs that require a full re-synch will contact their
> >> > replication
> >> > partners to request the partial attribute set for the domains that the
> >> > replication partner holds (either the sole one it is a DC for, or if it
> >> > is
> >> > a
> >> > GC then all the partitions)
> >> >
> >>
> >> Do you know what a GC holds ? It holds a read write copy of the domain
> >> naming context (all the objects and their attributes) for the domain it
> >> is a
> >> DC in. It then also holds a read only copy of every other domain naming
> >> context (all objects but only some of their attributes) for every other
> >> domain in the forest.
> >>
> >> > 4. Do all the GCs in the forest do a full replication or just the GCs
> >> > in
> >> > the
> >> > Domain? I'm a little confused. I've never been in an environment this
> >> > big
> >> > where replication was such a big issue.
> >> >
> >>
> >> Yes all GCs in a forest will do a full resynch in Windows 2000 if you
> >> change
> >> the partial attribute set in the required way.
> >>
> >>
> >>
> >> --
> >>
> >> Regards,
> >>
> >> Mike
> >> --
> >> Mike Brannigan [Microsoft]
> >>
> >> This posting is provided "AS IS" with no warranties, and confers no
> >> rights
> >>
> >> Please note I cannot respond to e-mailed questions, please use these
> >> newsgroups
> >>
> >> "Eshprof" <Eshprof@discussions.microsoft.com> wrote in message
> >> news:5A570124-0F25-46DD-84B4-2C629BC43E53@microsoft.com...
> >> > Thank you. Let me add a few more questions for clarification:
> >> >
> >> > I read from the "Windows 2000 Active Directory Black Book" that when
> >> > there
> >> > is a re-synch, the current GC information is discarded and rebuilt from
> >> > scratch.
> >> >
> >> > 1.If the GC information is discarded and rebuilt, then with what
> >> > machine
> >> > does it start? Is that accurate information or does a GC just contact
> >> > the
> >> > other GCs to make sure they are "all on the same page"?
> >> >
> >> > 2. Does it truly discard the data and start afresh? Discarding the
> >> > data
> >> > concerns me, because our ntds.dit file is approximately 8.6GB. Would
> >> > all
> >> > 8.6GB be replicated or just the changes, and then the GCs just confirm
> >> > they
> >> > are all in synch? Which GC is the base-line?
> >> >
> >> > 3. Thank you so much for your answers. I am though, not quite grasping
> >> > your
> >> > answer "The GCs that require a full re-synch will contact their
> >> > replication
> >> > partners to request the partial attribute set for the domains that the
> >> > replication partner holds (either the sole one it is a DC for, or if it
> >> > is
> >> > a
> >> > GC then all the partitions)
> >> >
> >> > 4. Do all the GCs in the forest do a full replication or just the GCs
> >> > in
> >> > the
> >> > Domain? I'm a little confused. I've never been in an environment this
> >> > big
> >> > where replication was such a big issue.
> >> >
> >> > I appreciate ALL the input you can give!
> >> >
> >> > Thanks!
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> > "Mike Brannigan [MSFT]" wrote:
> >> >
> >> >> "Eshprof" <Eshprof@discussions.microsoft.com> wrote in message
> >> >> news:7EC8AAA1-2190-4AC4-9A26-D08A13AB6072@microsoft.com...
> >> >> > We are in the planning stage of an SMS installation which will
> >> >> > change
> >> >> > the
> >> >> > schema. That will in turn kick off a full GC replication. So I
> >> >> > have
> >> >> > three
> >> >> > questions...
> >> >>
> >> >> Since you mention that you are expecting your schema changes to kick
> >> >> off
> >> >> a
> >> >> full GC rebuild then you must still be using Windows 2000 Active
> >> >> Directory
> >> >> (since 2003 fixed this issue).
> >> >>
> >> >> To address your questions.
> >> >> > 1. How do I find out how big the GG is?
> >> >>
> >> >> The size of the global catalog is the size of the ntds.dit file on a
> >> >> GC
> >> >> server.
> >> >>
> >> >> > 2. How does the GC do a full replication? ie does it first rebuild
> >> >> > on
> >> >> > the
> >> >> > machine that acts as the schema master and then update all the CG
> >> >> > Servers
> >> >> > at
> >> >> > once?
> >> >>
> >> >> What is a full re-sync?>
> >> >> > 3. How would I back up the schema so I can bring it back to its
> >> >> > original
> >> >> > state in case of a failure? I guessing that I can't since you can't
> >> >> > undo
> >> >> > schema changes.
> >> >> >
> >> >>
> >> >> You cannot recover a Schema from a backup in Windows 2000. You must
> >> >> be
> >> >> confident of your schema changes prior to live deployment through your
> >> >> testing and deployment process.
> >> >>
> >> >>
> >> >>
> >> >> --
> >> >>
> >> >> Regards,
> >> >>
> >> >> Mike
> >> >> --
> >> >> Mike Brannigan [Microsoft]
> >> >>
> >> >> This posting is provided "AS IS" with no warranties, and confers no
> >> >> rights
> >> >>
> >> >> Please note I cannot respond to e-mailed questions, please use these
> >> >> newsgroups
> >> >>
> >> >> "Eshprof" <Eshprof@discussions.microsoft.com> wrote in message
> >> >> news:7EC8AAA1-2190-4AC4-9A26-D08A13AB6072@microsoft.com...
> >> >> > We are in the planning stage of an SMS installation which will
> >> >> > change
> >> >> > the
> >> >> > schema. That will in turn kick off a full GC replication. So I
> >> >> > have
> >> >> > three
> >> >> > questions...
> >> >> >
> >> >> > 1. How do I find out how big the GG is?
> >> >> > 2. How does the GC do a full replication? ie does it first rebuild
> >> >> > on
> >> >> > the
> >> >> > machine that acts as the schema master and then update all the CG
> >> >> > Servers
> >> >> > at
> >> >> > once?
> >> >> > 3. How would I back up the schema so I can bring it back to its
> >> >> > original
> >> >> > state in case of a failure? I guessing that I can't since you can't
> >> >> > undo
> >> >> > schema changes.
> >> >> >
> >> >> > Thanks.
> >> >>
> >> >>
> >> >>
> >>
> >>
> >>
>
>
>

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