Discussion:
DFS failover delay
(too old to reply)
systems
2008-07-08 15:02:03 UTC
Permalink
Hello

I have configured DFS in a test environment with 3 DFS namespace hosts for
fault tolerance. Replication groups have also been setup with the data
replicating between each of the 3 hosts. Each host is located at a different
site though they are connected by high speed links.
Whilst all 3 DFS namespace hosts are online, access to the DFS folder
structure works perfectly. However, if a host is taken offline, client pcs
located on the same site experience 15-30 second delays in accessing the DFS
root and folder targets (at another site), eg, \\contoso.com\public\example.
This delay is repeated even once the client pc is connected and is browing
sub folders. If the clients connect without using the DFS namespace eg,
\\server\shared\example the connection is instantaneous. Client pcs located
at the other sites are uneffected.
As soon as the offline server is brough back online service resumes
immediately. Any ideas what could be causing these delays?

Many thanks
DaveMills
2008-07-08 17:54:09 UTC
Permalink
I have seen this sort of thing on a single site. The DFS client seems to query
the servers in order and waits for a timeout before checking the next server.
What's more Windows Explorer seems to lock up while it waits. This can be very
frustrating for the users. (and the help desk)

It is a bit like NT4 DNS looks were with 60 sec timeouts. In W2k DNS fired of
the second request just a second or 2 after the first and then accepted the
first answer to be returned. I think DFS would be vastly improved by a similar
algorithm.
Post by systems
Hello
I have configured DFS in a test environment with 3 DFS namespace hosts for
fault tolerance. Replication groups have also been setup with the data
replicating between each of the 3 hosts. Each host is located at a different
site though they are connected by high speed links.
Whilst all 3 DFS namespace hosts are online, access to the DFS folder
structure works perfectly. However, if a host is taken offline, client pcs
located on the same site experience 15-30 second delays in accessing the DFS
root and folder targets (at another site), eg, \\contoso.com\public\example.
This delay is repeated even once the client pc is connected and is browing
sub folders. If the clients connect without using the DFS namespace eg,
\\server\shared\example the connection is instantaneous. Client pcs located
at the other sites are uneffected.
As soon as the offline server is brough back online service resumes
immediately. Any ideas what could be causing these delays?
Many thanks
--
Dave Mills
There are 10 type of people, those that understand binary and those that don't.
Huseby", "Tom R
2008-07-09 21:52:31 UTC
Permalink
Hi Dave,

The simple fix for you sounds like to configure another DFS namespace
root in each location. I assume your test environment has DFSr servers
also hosting namespaces? Clients slow down considerably when they have
to access a namespace root across the WAN. Or you could configure
another machine other than your site host as the local namespace server.


-Tom Huseby


-----Original Message-----
From: DaveMills [mailto:***@newsgroup.nospam]
Posted At: Tuesday, July 08, 2008 12:54 PM
Posted To: microsoft.public.windows.server.dfs_frs
Conversation: DFS failover delay
Subject: Re: DFS failover delay

I have seen this sort of thing on a single site. The DFS client seems to
query
the servers in order and waits for a timeout before checking the next
server.
What's more Windows Explorer seems to lock up while it waits. This can
be very
frustrating for the users. (and the help desk)

It is a bit like NT4 DNS looks were with 60 sec timeouts. In W2k DNS
fired of
the second request just a second or 2 after the first and then accepted
the
first answer to be returned. I think DFS would be vastly improved by a
similar
algorithm.


On Tue, 8 Jul 2008 08:02:03 -0700, systems
Post by systems
Hello
I have configured DFS in a test environment with 3 DFS namespace hosts for
fault tolerance. Replication groups have also been setup with the data
replicating between each of the 3 hosts. Each host is located at a different
site though they are connected by high speed links.
Whilst all 3 DFS namespace hosts are online, access to the DFS folder
structure works perfectly. However, if a host is taken offline, client pcs
located on the same site experience 15-30 second delays in accessing the DFS
root and folder targets (at another site), eg,
\\contoso.com\public\example.
Post by systems
This delay is repeated even once the client pc is connected and is browing
sub folders. If the clients connect without using the DFS namespace eg,
\\server\shared\example the connection is instantaneous. Client pcs located
at the other sites are uneffected.
As soon as the offline server is brough back online service resumes
immediately. Any ideas what could be causing these delays?
Many thanks
--
Dave Mills
There are 10 type of people, those that understand binary and those that
don't.
systems
2008-07-10 15:28:02 UTC
Permalink
Thanks for the suggestion Dave.

I configured another DFS namespace host at one site and then tested. It
seems that whichever namespace host the client PC has as the first in it's
referral list always needs to be online. If this host is taken offline then
there is a delay in connection, even if there is another DFS host on the same
LAN subnet.

To see if there was a problem connecting to DFS hosts over a WAN I also
removed all DFS hosts from a particular site. This forced the clients to
connect over the WAN and there were no delays in connection.

Any ideas why the client still tries to connect to the host that is forst in
the referral list even if it is offline?

Thanks
Post by Huseby", "Tom R
Hi Dave,
The simple fix for you sounds like to configure another DFS namespace
root in each location. I assume your test environment has DFSr servers
also hosting namespaces? Clients slow down considerably when they have
to access a namespace root across the WAN. Or you could configure
another machine other than your site host as the local namespace server.
-Tom Huseby
-----Original Message-----
Posted At: Tuesday, July 08, 2008 12:54 PM
Posted To: microsoft.public.windows.server.dfs_frs
Conversation: DFS failover delay
Subject: Re: DFS failover delay
I have seen this sort of thing on a single site. The DFS client seems to query
the servers in order and waits for a timeout before checking the next server.
What's more Windows Explorer seems to lock up while it waits. This can be very
frustrating for the users. (and the help desk)
It is a bit like NT4 DNS looks were with 60 sec timeouts. In W2k DNS fired of
the second request just a second or 2 after the first and then accepted the
first answer to be returned. I think DFS would be vastly improved by a similar
algorithm.
On Tue, 8 Jul 2008 08:02:03 -0700, systems
Post by systems
Hello
I have configured DFS in a test environment with 3 DFS namespace hosts
for
Post by systems
fault tolerance. Replication groups have also been setup with the data
replicating between each of the 3 hosts. Each host is located at a
different
Post by systems
site though they are connected by high speed links.
Whilst all 3 DFS namespace hosts are online, access to the DFS folder
structure works perfectly. However, if a host is taken offline, client
pcs
Post by systems
located on the same site experience 15-30 second delays in accessing
the DFS
Post by systems
root and folder targets (at another site), eg,
\\contoso.com\public\example.
Post by systems
This delay is repeated even once the client pc is connected and is
browing
Post by systems
sub folders. If the clients connect without using the DFS namespace eg,
\\server\shared\example the connection is instantaneous. Client pcs
located
Post by systems
at the other sites are uneffected.
As soon as the offline server is brough back online service resumes
immediately. Any ideas what could be causing these delays?
Many thanks
--
Dave Mills
There are 10 type of people, those that understand binary and those that don't.
DaveMills
2008-07-13 07:26:25 UTC
Permalink
Post by systems
Thanks for the suggestion Dave.
I configured another DFS namespace host at one site and then tested. It
seems that whichever namespace host the client PC has as the first in it's
referral list always needs to be online. If this host is taken offline then
there is a delay in connection, even if there is another DFS host on the same
LAN subnet.
That is my experience too.
Post by systems
To see if there was a problem connecting to DFS hosts over a WAN I also
removed all DFS hosts from a particular site. This forced the clients to
connect over the WAN and there were no delays in connection.
Any ideas why the client still tries to connect to the host that is forst in
the referral list even if it is offline?
I guess because that is how it determines it is offline. It should be changed to
wait only 2 seconds before trying the next in the list.
Post by systems
Thanks
Post by Huseby", "Tom R
Hi Dave,
The simple fix for you sounds like to configure another DFS namespace
root in each location. I assume your test environment has DFSr servers
also hosting namespaces? Clients slow down considerably when they have
to access a namespace root across the WAN. Or you could configure
another machine other than your site host as the local namespace server.
-Tom Huseby
-----Original Message-----
Posted At: Tuesday, July 08, 2008 12:54 PM
Posted To: microsoft.public.windows.server.dfs_frs
Conversation: DFS failover delay
Subject: Re: DFS failover delay
I have seen this sort of thing on a single site. The DFS client seems to query
the servers in order and waits for a timeout before checking the next server.
What's more Windows Explorer seems to lock up while it waits. This can be very
frustrating for the users. (and the help desk)
It is a bit like NT4 DNS looks were with 60 sec timeouts. In W2k DNS fired of
the second request just a second or 2 after the first and then accepted the
first answer to be returned. I think DFS would be vastly improved by a similar
algorithm.
On Tue, 8 Jul 2008 08:02:03 -0700, systems
Post by systems
Hello
I have configured DFS in a test environment with 3 DFS namespace hosts
for
Post by systems
fault tolerance. Replication groups have also been setup with the data
replicating between each of the 3 hosts. Each host is located at a
different
Post by systems
site though they are connected by high speed links.
Whilst all 3 DFS namespace hosts are online, access to the DFS folder
structure works perfectly. However, if a host is taken offline, client
pcs
Post by systems
located on the same site experience 15-30 second delays in accessing
the DFS
Post by systems
root and folder targets (at another site), eg,
\\contoso.com\public\example.
Post by systems
This delay is repeated even once the client pc is connected and is
browing
Post by systems
sub folders. If the clients connect without using the DFS namespace eg,
\\server\shared\example the connection is instantaneous. Client pcs
located
Post by systems
at the other sites are uneffected.
As soon as the offline server is brough back online service resumes
immediately. Any ideas what could be causing these delays?
Many thanks
--
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.
arkadja
2009-05-05 09:58:02 UTC
Permalink
i've your same problem.

Someone know the solution?
Post by systems
Hello
I have configured DFS in a test environment with 3 DFS namespace hosts for
fault tolerance. Replication groups have also been setup with the data
replicating between each of the 3 hosts. Each host is located at a different
site though they are connected by high speed links.
Whilst all 3 DFS namespace hosts are online, access to the DFS folder
structure works perfectly. However, if a host is taken offline, client pcs
located on the same site experience 15-30 second delays in accessing the DFS
root and folder targets (at another site), eg, \\contoso.com\public\example.
This delay is repeated even once the client pc is connected and is browing
sub folders. If the clients connect without using the DFS namespace eg,
\\server\shared\example the connection is instantaneous. Client pcs located
at the other sites are uneffected.
As soon as the offline server is brough back online service resumes
immediately. Any ideas what could be causing these delays?
Many thanks
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