DFS failover delay

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

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 <>
wrote:

>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.

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

"Huseby" <Huseby>, "Tom R" wrote:

> 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]
> 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
> <>
> wrote:
>
> >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.
>
>

On Thu, 10 Jul 2008 08:28:02 -0700, systems <>
wrote:

>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.
>
>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.
>
>Thanks
>
>"Huseby" <Huseby>, "Tom R" wrote:
>
>> 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]
>> 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
>> <>
>> wrote:
>>
>> >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.
>>
>>
--
Dave Mills
There are 10 type of people, those that understand binary and those that don't.

i've your same problem.

Someone know the solution?


"systems" wrote:

> 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