Discussion:
DFS Fault Tolerance
(too old to reply)
mwest
2006-03-21 20:14:31 UTC
Permalink
Hi, Is there such a thing?
I thought I found it in an article about replication, but that turned out to
be about having multiple copies of the files.
I.E. Who cares if you have ten copies of a file if you can't get to it.
Win2k3 domain with two or more DC's
Multiple file servers
Multiple "Domain DFS roots" created on the PDC
If the PDC is offline can anyone get to a drive mapping of
\\domain\DFS-Root ?
I thought that since they were created on a DC that any of the DC's could
fill the DFS requests.
It seems that when this DC is offline so is DFS, even though there are other
DC's running.
Is there a way of making DFS Fault Tolerant?
Richard Chinn [MSFT]
2006-03-21 21:37:24 UTC
Permalink
The DFS FAQ may be of use to you. In particular, the section called
DFS Availablity near the bottom on the page.

http://www.microsoft.com/windowsserver2003/techinfo/overview/dfsfaq.mspx

Here is a snippet from the FAQ.

Q. How do I ensure the availability of a DFS namespace?
A. The answer depends on type of namespace: stand-alone or
domain-based.

For stand-alone DFS namespaces, you ensure the availability of a
stand-alone DFS root by creating it on the cluster storage of a
clustered file server by using the Cluster Administrator snap-in.

For domain-based DFS namespaces, you ensure the availability of
domain-based DFS roots by creating multiple root targets on
nonclustered file servers or on the local storage of the nodes of
server clusters. (Domain-based DFS roots cannot be created on cluster
storage.) All root targets must belong to the same domain. To create
root targets, use the Distributed File System snap-in or the
Dfsutil.exe command-line tool.

To ensure the availability of domain-based DFS roots, you must have at
least two domain controllers and two root targets within the domain
that is hosting the root. If you have only one domain controller and
it becomes unavailable, the namespace is inaccessible. Similarly, if
you have only a single root target, and the server hosting the root
target is unavailable, the namespace is also unavailable.

Note that DFS (Namespaces) is often used in conjunction with some form
of file replication (usually FRS or DFS Replication that is new in R2,
but it can even be robocopy). When you have multiple link targets
that have files replicated between them, you can have DFS fail over to
an alternate target when one link target becomes unavailble. Here is
another snippet from the FAQ.

Q. How do I increase the availability of data in link targets?
A. There are two ways to increase the availability of data in link
targets:

• Create a single link that points to a link target on a clustered
file server.

• Create multiple link targets and replicate content among them.

You can create link targets that point to clustered file servers in
both types of namespaces. However, if you want to replicate content
among multiple link targets, the type of namespace determines your
replication options.

Using Replication in Stand-alone DFS Namespaces
In a stand-alone DFS namespace, you can replicate the files by copying
them manually, using scripts, using Robocopy.exe, which is available
in the Microsoft Windows Server 2003 Deployment Kit, or by using other
replication tools. The Distributed File System snap-in does not
provide a user interface for configuring FRS replication in
stand-alone DFS namespaces. To configure replication manually, consult
the documentation supplied with your replication tools.

Using Replication in Domain-based DFS Namespaces
The Distributed File System snap-in in Windows Server 2003 provides a
user interface for creating the FRS topology and schedule on servers
running Windows Server 2003. Using FRS in a domain-based DFS namespace
is optional; you can also replicate files by copying them manually or
by using non-Microsoft replication tools.

--Richard

Please post FRS related questions to
microsoft.public.windows.server.dfs_frs and prefix the subject line
with "FRS:" to make it easier to spot. Note that FRS is used to
replicate SYSVOL on domain controllers and DFS root and link targets.

DFS Replication is a new file replication engine in
Windows Server 2003 R2. It is used to replicate folders between
computers with or without DFS Namespaces.

For additional FRS resources, please visit
http://www.microsoft.com/frs.

For additional DFS Replication resources, please visit
http://www.microsoft.com/windowsserver2003/technologies/storage/dfs/default.mspx

This posting is provided "AS IS" with no warranties, and confers no
rights.
Post by mwest
Hi, Is there such a thing?
I thought I found it in an article about replication, but that turned out to
be about having multiple copies of the files.
I.E. Who cares if you have ten copies of a file if you can't get to it.
Win2k3 domain with two or more DC's
Multiple file servers
Multiple "Domain DFS roots" created on the PDC
If the PDC is offline can anyone get to a drive mapping of
\\domain\DFS-Root ?
I thought that since they were created on a DC that any of the DC's could
fill the DFS requests.
It seems that when this DC is offline so is DFS, even though there are other
DC's running.
Is there a way of making DFS Fault Tolerant?
mwest
2006-03-24 17:28:19 UTC
Permalink
When the PDC is offline they get the standard "inaccesible" message, even
though there still is a running DC.
The login mapping is \\Domain\DFSRoot.
Below that are links to shares on various servers.
Each DFS root provides the links needed by the group that has it mapped.
DC replication, when initiated through AD Sites & Services works fine.
The following command does not display any errors:
dcdiag /s:SERVER /fix /c /v /a
We run 2kp and xp-sp2 both with identical results.
We also have a WUS server so all the latest fixes issued are applied.
Would it matter that the mapping is to \\domain\DFSRoot and not
\\domain.com\DFSRoot
Post by Richard Chinn [MSFT]
The DFS FAQ may be of use to you. In particular, the section called
DFS Availablity near the bottom on the page.
http://www.microsoft.com/windowsserver2003/techinfo/overview/dfsfaq.mspx
Here is a snippet from the FAQ.
Q. How do I ensure the availability of a DFS namespace?
A. The answer depends on type of namespace: stand-alone or
domain-based.
For stand-alone DFS namespaces, you ensure the availability of a
stand-alone DFS root by creating it on the cluster storage of a
clustered file server by using the Cluster Administrator snap-in.
For domain-based DFS namespaces, you ensure the availability of
domain-based DFS roots by creating multiple root targets on
nonclustered file servers or on the local storage of the nodes of
server clusters. (Domain-based DFS roots cannot be created on cluster
storage.) All root targets must belong to the same domain. To create
root targets, use the Distributed File System snap-in or the
Dfsutil.exe command-line tool.
To ensure the availability of domain-based DFS roots, you must have at
least two domain controllers and two root targets within the domain
that is hosting the root. If you have only one domain controller and
it becomes unavailable, the namespace is inaccessible. Similarly, if
you have only a single root target, and the server hosting the root
target is unavailable, the namespace is also unavailable.
Note that DFS (Namespaces) is often used in conjunction with some form
of file replication (usually FRS or DFS Replication that is new in R2,
but it can even be robocopy). When you have multiple link targets
that have files replicated between them, you can have DFS fail over to
an alternate target when one link target becomes unavailble. Here is
another snippet from the FAQ.
Q. How do I increase the availability of data in link targets?
A. There are two ways to increase the availability of data in link
. Create a single link that points to a link target on a clustered
file server.
. Create multiple link targets and replicate content among them.
You can create link targets that point to clustered file servers in
both types of namespaces. However, if you want to replicate content
among multiple link targets, the type of namespace determines your
replication options.
Using Replication in Stand-alone DFS Namespaces
In a stand-alone DFS namespace, you can replicate the files by copying
them manually, using scripts, using Robocopy.exe, which is available
in the Microsoft Windows Server 2003 Deployment Kit, or by using other
replication tools. The Distributed File System snap-in does not
provide a user interface for configuring FRS replication in
stand-alone DFS namespaces. To configure replication manually, consult
the documentation supplied with your replication tools.
Using Replication in Domain-based DFS Namespaces
The Distributed File System snap-in in Windows Server 2003 provides a
user interface for creating the FRS topology and schedule on servers
running Windows Server 2003. Using FRS in a domain-based DFS namespace
is optional; you can also replicate files by copying them manually or
by using non-Microsoft replication tools.
--Richard
Please post FRS related questions to
microsoft.public.windows.server.dfs_frs and prefix the subject line
with "FRS:" to make it easier to spot. Note that FRS is used to
replicate SYSVOL on domain controllers and DFS root and link targets.
DFS Replication is a new file replication engine in
Windows Server 2003 R2. It is used to replicate folders between
computers with or without DFS Namespaces.
For additional FRS resources, please visit
http://www.microsoft.com/frs.
For additional DFS Replication resources, please visit
http://www.microsoft.com/windowsserver2003/technologies/storage/dfs/default.mspx
This posting is provided "AS IS" with no warranties, and confers no
rights.
Post by mwest
Hi, Is there such a thing?
I thought I found it in an article about replication, but that turned out to
be about having multiple copies of the files.
I.E. Who cares if you have ten copies of a file if you can't get to it.
Win2k3 domain with two or more DC's
Multiple file servers
Multiple "Domain DFS roots" created on the PDC
If the PDC is offline can anyone get to a drive mapping of
\\domain\DFS-Root ?
I thought that since they were created on a DC that any of the DC's could
fill the DFS requests.
It seems that when this DC is offline so is DFS, even though there are other
DC's running.
Is there a way of making DFS Fault Tolerant?
mwest
2006-03-22 01:20:08 UTC
Permalink
Hi,
I've downloaded that doc and printed it and will read it tonight, but at
first glance it seems to be saying that if you're setting up Domain based
DFS you will have to manually do it on every DC you want it on.

The file servers are duplexed RAID5 [RAID51] in one physical location so I
don't need file replication.
Just don't want DFS to be dependent on one DC.
Do I have to set DFS up multiple times in order to get redundancy in a
single
domain?
Dave Mills
2006-03-22 09:25:21 UTC
Permalink
Post by mwest
Hi,
I've downloaded that doc and printed it and will read it tonight, but at
first glance it seems to be saying that if you're setting up Domain based
DFS you will have to manually do it on every DC you want it on.
The file servers are duplexed RAID5 [RAID51] in one physical location so I
don't need file replication.
Just don't want DFS to be dependent on one DC.
Do I have to set DFS up multiple times in order to get redundancy in a
single
domain?
Make sure you have 2 or more DCs. Set up Domain based DFS once. Add at least 2
root servers.
--
Dave Mills
There are 10 type of people, those that understand binary and those that don't.
mwest
2006-03-23 17:49:13 UTC
Permalink
So if I have 10 servers I have to setup DFS 10 times?
That includes all the Roots, Roots Targets and links?
Post by Dave Mills
Post by mwest
Hi,
I've downloaded that doc and printed it and will read it tonight, but at
first glance it seems to be saying that if you're setting up Domain based
DFS you will have to manually do it on every DC you want it on.
The file servers are duplexed RAID5 [RAID51] in one physical location so I
don't need file replication.
Just don't want DFS to be dependent on one DC.
Do I have to set DFS up multiple times in order to get redundancy in a
single
domain?
Make sure you have 2 or more DCs. Set up Domain based DFS once. Add at least 2
root servers.
--
Dave Mills
There are 10 type of people, those that understand binary and those that don't.
Dave Mills
2006-03-24 22:11:07 UTC
Permalink
Post by mwest
So if I have 10 servers I have to setup DFS 10 times?
That includes all the Roots, Roots Targets and links?
No, you nominate which servers will host a dfs root. The root is set up once and
then replicated to the other roots you have nominated.

Of course you have to nominate each server that you want to be a DFS Root
replica but you don't need to recreate it content.
Post by mwest
Post by Dave Mills
Post by mwest
Hi,
I've downloaded that doc and printed it and will read it tonight, but at
first glance it seems to be saying that if you're setting up Domain based
DFS you will have to manually do it on every DC you want it on.
The file servers are duplexed RAID5 [RAID51] in one physical location so I
don't need file replication.
Just don't want DFS to be dependent on one DC.
Do I have to set DFS up multiple times in order to get redundancy in a
single
domain?
Make sure you have 2 or more DCs. Set up Domain based DFS once. Add at least 2
root servers.
--
Dave Mills
There are 10 type of people, those that understand binary and those that don't.
--
Dave Mills
There are 10 type of people, those that understand binary and those that don't.
mwest
2006-03-24 23:01:48 UTC
Permalink
Hi,
I didn't see that in the "dfsgui.msc" how to I setup DFS Root replicas?
Post by Dave Mills
Post by mwest
So if I have 10 servers I have to setup DFS 10 times?
That includes all the Roots, Roots Targets and links?
No, you nominate which servers will host a dfs root. The root is set up once and
then replicated to the other roots you have nominated.
Of course you have to nominate each server that you want to be a DFS Root
replica but you don't need to recreate it content.
Post by mwest
Post by Dave Mills
Post by mwest
Hi,
I've downloaded that doc and printed it and will read it tonight, but at
first glance it seems to be saying that if you're setting up Domain based
DFS you will have to manually do it on every DC you want it on.
The file servers are duplexed RAID5 [RAID51] in one physical location so I
don't need file replication.
Just don't want DFS to be dependent on one DC.
Do I have to set DFS up multiple times in order to get redundancy in a
single
domain?
Make sure you have 2 or more DCs. Set up Domain based DFS once. Add at least 2
root servers.
--
Dave Mills
There are 10 type of people, those that understand binary and those that don't.
--
Dave Mills
There are 10 type of people, those that understand binary and those that don't.
Dave Mills
2006-03-25 06:37:52 UTC
Permalink
Post by mwest
Hi,
I didn't see that in the "dfsgui.msc" how to I setup DFS Root replicas?
Right click the domain and select New Root Target or Add Namespace Server
(depends upon which DFS tool you are using)
Post by mwest
Post by Dave Mills
Post by mwest
So if I have 10 servers I have to setup DFS 10 times?
That includes all the Roots, Roots Targets and links?
No, you nominate which servers will host a dfs root. The root is set up once and
then replicated to the other roots you have nominated.
Of course you have to nominate each server that you want to be a DFS Root
replica but you don't need to recreate it content.
Post by mwest
Post by Dave Mills
Post by mwest
Hi,
I've downloaded that doc and printed it and will read it tonight, but at
first glance it seems to be saying that if you're setting up Domain based
DFS you will have to manually do it on every DC you want it on.
The file servers are duplexed RAID5 [RAID51] in one physical location so I
don't need file replication.
Just don't want DFS to be dependent on one DC.
Do I have to set DFS up multiple times in order to get redundancy in a
single
domain?
Make sure you have 2 or more DCs. Set up Domain based DFS once. Add at least 2
root servers.
--
Dave Mills
There are 10 type of people, those that understand binary and those that don't.
--
Dave Mills
There are 10 type of people, those that understand binary and those that don't.
--
Dave Mills
There are 10 type of people, those that understand binary and those that don't.
Rob
2006-03-24 15:41:37 UTC
Permalink
Try adding the other DC as a namespace server.
Post by mwest
Hi,
I've downloaded that doc and printed it and will read it tonight, but at
first glance it seems to be saying that if you're setting up Domain based
DFS you will have to manually do it on every DC you want it on.
The file servers are duplexed RAID5 [RAID51] in one physical location so I
don't need file replication.
Just don't want DFS to be dependent on one DC.
Do I have to set DFS up multiple times in order to get redundancy in a
single
domain?
mwest
2006-03-24 17:24:34 UTC
Permalink
I'm not sure what that means.
Post by Rob
Try adding the other DC as a namespace server.
Post by mwest
Hi,
I've downloaded that doc and printed it and will read it tonight, but at
first glance it seems to be saying that if you're setting up Domain based
DFS you will have to manually do it on every DC you want it on.
The file servers are duplexed RAID5 [RAID51] in one physical location so I
don't need file replication.
Just don't want DFS to be dependent on one DC.
Do I have to set DFS up multiple times in order to get redundancy in a
single
domain?
Rob
2006-03-24 17:37:35 UTC
Permalink
When you click on the individual Namespace items, there should be a tab on
the right labelled Namespace Servers. Add another DC to this list. This
won't change where the actual files are located (which won't be accessible
if THAT server goes down). It's another server which will tell clients
where the files are located for \\domain.com\share. Keep in mind that if
the PDC is inaccessible, then this will fail, since all namespace servers
have to reference the PDC emulator.

HTH,
-Rob
Post by mwest
I'm not sure what that means.
Post by Rob
Try adding the other DC as a namespace server.
Post by mwest
Hi,
I've downloaded that doc and printed it and will read it tonight, but at
first glance it seems to be saying that if you're setting up Domain based
DFS you will have to manually do it on every DC you want it on.
The file servers are duplexed RAID5 [RAID51] in one physical location so I
don't need file replication.
Just don't want DFS to be dependent on one DC.
Do I have to set DFS up multiple times in order to get redundancy in a
single
domain?
mwest
2006-03-24 17:55:55 UTC
Permalink
Hi,
What MMC are you using?
I only have the "dfsgui.msc" and don't see the areas (tabs) you describe.
I see "General" and/or "Publish" if you go to an objects properties.
Luckily the file servera haven't gone down in years it's the reffereal
service... "DFS" that seems to be the problem.
So by "namespace" you mean DFS itself? That is, what I have setup in DFS.
And you're saying that to use DFS would be to make the entire company
dependant on the PDC?
Post by Rob
When you click on the individual Namespace items, there should be a tab on
the right labelled Namespace Servers. Add another DC to this list. This
won't change where the actual files are located (which won't be accessible
if THAT server goes down). It's another server which will tell clients
where the files are located for \\domain.com\share. Keep in mind that if
the PDC is inaccessible, then this will fail, since all namespace servers
have to reference the PDC emulator.
HTH,
-Rob
Post by mwest
I'm not sure what that means.
Post by Rob
Try adding the other DC as a namespace server.
Post by mwest
Hi,
I've downloaded that doc and printed it and will read it tonight, but at
first glance it seems to be saying that if you're setting up Domain based
DFS you will have to manually do it on every DC you want it on.
The file servers are duplexed RAID5 [RAID51] in one physical location so I
don't need file replication.
Just don't want DFS to be dependent on one DC.
Do I have to set DFS up multiple times in order to get redundancy in a
single
domain?
Dave Mills
2006-03-24 22:16:26 UTC
Permalink
Post by Rob
When you click on the individual Namespace items, there should be a tab on
the right labelled Namespace Servers. Add another DC to this list. This
won't change where the actual files are located (which won't be accessible
if THAT server goes down). It's another server which will tell clients
where the files are located for \\domain.com\share. Keep in mind that if
the PDC is inaccessible, then this will fail, since all namespace servers
have to reference the PDC emulator.
This is not what is documented in the How DFS Works document. The PDC seems to
take the role of creating and changing the namespace but other DCs can provide
referrals. There are issues regarding using NetBIOS or DNS names that you should
read up on too. NetBIOS is the default and DNS requires registry changes.
NetBIOS will need WINS to work in multiple subnets.
Post by Rob
HTH,
-Rob
Post by mwest
I'm not sure what that means.
Post by Rob
Try adding the other DC as a namespace server.
Post by mwest
Hi,
I've downloaded that doc and printed it and will read it tonight, but at
first glance it seems to be saying that if you're setting up Domain based
DFS you will have to manually do it on every DC you want it on.
The file servers are duplexed RAID5 [RAID51] in one physical location so I
don't need file replication.
Just don't want DFS to be dependent on one DC.
Do I have to set DFS up multiple times in order to get redundancy in a
single
domain?
--
Dave Mills
There are 10 type of people, those that understand binary and those that don't.
Continue reading on narkive:
Loading...