Fail over - DNS change

Hi,

In case of failover to standby server, what is theest way to redirect
client applications to new server?
1) DNS name change -- not viable due to Caching issue.

IS there any alternate like Oracle's onames/LDAP for resolving name
with sql server?

Can use Sever alias?

Thanksbarbara_2003@.hotmail.com (barbara) wrote in message news:<5cd01256.0408221348.259e22d1@.posting.google.com>...
> Hi,
> In case of failover to standby server, what is theest way to redirect
> client applications to new server?
> 1) DNS name change -- not viable due to Caching issue.
> IS there any alternate like Oracle's onames/LDAP for resolving name
> with sql server?
> Can use Sever alias?
> Thanks

There's no equivalent to Oracle's naming solutions, since MSSQL uses
the operating system for name resolution. If you can't use DNS, then
you would have to look at modifying connection strings or ODBC DSNs in
your applications. This is easier for some types of applications than
others, of course.

Simon|||Please share any other recommendations.

sql@.hayes.ch (Simon Hayes) wrote in message news:<60cd0137.0408230548.39882eda@.posting.google.com>...
> barbara_2003@.hotmail.com (barbara) wrote in message news:<5cd01256.0408221348.259e22d1@.posting.google.com>...
> > Hi,
> > In case of failover to standby server, what is theest way to redirect
> > client applications to new server?
> > 1) DNS name change -- not viable due to Caching issue.
> > IS there any alternate like Oracle's onames/LDAP for resolving name
> > with sql server?
> > Can use Sever alias?
> > Thanks
> There's no equivalent to Oracle's naming solutions, since MSSQL uses
> the operating system for name resolution. If you can't use DNS, then
> you would have to look at modifying connection strings or ODBC DSNs in
> your applications. This is easier for some types of applications than
> others, of course.
> Simon|||Sinon,

Thanks for reply. How does it uses OS for name resolution in case of
multiple instances? Could we use multiple IP address feature of sql
2000 for fail over purpose? Using virtual IP, but without using
clustering.

sql@.hayes.ch (Simon Hayes) wrote in message news:<60cd0137.0408230548.39882eda@.posting.google.com>...
> barbara_2003@.hotmail.com (barbara) wrote in message news:<5cd01256.0408221348.259e22d1@.posting.google.com>...
> > Hi,
> > In case of failover to standby server, what is theest way to redirect
> > client applications to new server?
> > 1) DNS name change -- not viable due to Caching issue.
> > IS there any alternate like Oracle's onames/LDAP for resolving name
> > with sql server?
> > Can use Sever alias?
> > Thanks
> There's no equivalent to Oracle's naming solutions, since MSSQL uses
> the operating system for name resolution. If you can't use DNS, then
> you would have to look at modifying connection strings or ODBC DSNs in
> your applications. This is easier for some types of applications than
> others, of course.
> Simon|||barbara_2003@.hotmail.com (barbara) wrote in message news:<5cd01256.0408240202.7bb670e8@.posting.google.com>...
> Sinon,
> Thanks for reply. How does it uses OS for name resolution in case of
> multiple instances? Could we use multiple IP address feature of sql
> 2000 for fail over purpose? Using virtual IP, but without using
> clustering.

<snip
The client resolves the server part of the instance name, then
connects to port 1434 to get back a list of instances and the ports
they listen on; it can then connect to the correct port for the
instance you requested. You can specify these ports explicitly using
the MSSQL Server Network Utility if you want to.

Clustering is the standard way to implement failover with MSSQL -
multiple instances aren't useful for high availability. You can check
these resources for more details:

http://www.microsoft.com/sql/techin...vailability.asp
http://www.microsoft.com/technet/pr...oy/sqlhalp.mspx

I'm not sure why you want to avoid clustering - if you have a business
need for any sort of high availability solution, then you have to make
sure you get the correct resources you need for that.

Simon|||Our vendor application (web based) doesn't support clustering. What
are the disadvantages of using NLB for failover? I've read it is not
advisable to use NLB for critical DB failovers. Is it true?

sql@.hayes.ch (Simon Hayes) wrote in message news:<60cd0137.0408240605.2c289511@.posting.google.com>...
> barbara_2003@.hotmail.com (barbara) wrote in message news:<5cd01256.0408240202.7bb670e8@.posting.google.com>...
> > Sinon,
> > Thanks for reply. How does it uses OS for name resolution in case of
> > multiple instances? Could we use multiple IP address feature of sql
> > 2000 for fail over purpose? Using virtual IP, but without using
> > clustering.
> <snip>
> The client resolves the server part of the instance name, then
> connects to port 1434 to get back a list of instances and the ports
> they listen on; it can then connect to the correct port for the
> instance you requested. You can specify these ports explicitly using
> the MSSQL Server Network Utility if you want to.
> Clustering is the standard way to implement failover with MSSQL -
> multiple instances aren't useful for high availability. You can check
> these resources for more details:
> http://www.microsoft.com/sql/techin...vailability.asp
> http://www.microsoft.com/technet/pr...oy/sqlhalp.mspx
> I'm not sure why you want to avoid clustering - if you have a business
> need for any sort of high availability solution, then you have to make
> sure you get the correct resources you need for that.
> Simon|||barbara_2003@.hotmail.com (barbara) wrote in message news:<5cd01256.0408241352.44eb3992@.posting.google.com>...
> Our vendor application (web based) doesn't support clustering. What
> are the disadvantages of using NLB for failover? I've read it is not
> advisable to use NLB for critical DB failovers. Is it true?

<snip
I have no idea, since I've never used NLB myself. See here:

http://www.microsoft.com/technet/pr...oy/hasog04.mspx

Simon