A/A or A/P

Hello:
I'm sort of new to clustering and some of these questions
popped into mind:
- From an administrative perspective, which of the two is
more easily manageable, Active/Active or Active/Passive?
- When would one want to use A/A or A/P (i.e. how to
evaluate key objectives to determine clustering type)
Thanks for your response.
Once you "get" clustering, A/A or A/P management is the same from a
clustering standpoint. From a SQL standpoint, A/A is more work, cause you
have another copy of SQL to manage.
It is not recommended to run A/A, most systems are not configured to handle
the double load upon failure.
Cheers,
Rod
MVP - Windows Server - Clustering
http://www.nw-america.com - Clustering
http://msmvps.com/clustering - Blog
"Rob" <anonymous@.discussions.microsoft.com> wrote in message
news:2fc901c4a23c$d284ea00$a601280a@.phx.gbl...
> Hello:
> I'm sort of new to clustering and some of these questions
> popped into mind:
> - From an administrative perspective, which of the two is
> more easily manageable, Active/Active or Active/Passive?
> - When would one want to use A/A or A/P (i.e. how to
> evaluate key objectives to determine clustering type)
> Thanks for your response.
|||Hi Rob,
A/P and A/A terminology does not really apply for SQL Server 2000. It was used for SQL 7.0 clustering.
* Single instance cluster: replaces an active/passive cluster. A single instance cluster means there is one SQL Server 2000 virtual server installed.
* Multiple instance cluster: replaces an active/active cluster. A multiple instance cluster is one in which there is more than one SQL Server 2000 virtual server installed. Because of the way the implementation of
clustering is different with SQL Server 2000, using the active/active terminology does not really apply. A multiple-instance cluster has up to four server nodes and supports up to 16 instances (1 default, 15 named or
16 named). Each SQL Server 2000 virtual server requires its own disk resources that cannot be used by other instances
I would recommend you to review Microsoft SQL Server 2000 Failover Clustering whitepaper to get a clear picture
Microsoft Whitepaper - SQL Server 2000 Failover Clustering
http://www.microsoft.com/technet/pro.../failclus.mspx
Although A/P and A/A are old terms, many still use it. For many, A/P means that there is just one instance of SQL Server 2000 running on the A node and nothing is running on P node. Many refer to A/A as first SQL
Server instance running on first A node and second SQL Server instance running on second A node. This way both nodes are being used. This is used very commonly by customers. The IMPORTANT thing is
that each node should have enough resources to host both the SQL Servers in case one node goes down. The above whitepaper has good scenarios and talks about how to configure the resources. A/P and
A/A terms work ok till two instances. With SQL 2K, we can have upto 16 instances on a two node cluster. I have seen customers having four instances of SQL Server on a two node cluster. what will this be called
now? So, its better to use that we have four instance SQL cluster on a two node windows MSCS. In case of a four instance SQL Cluster, each node should have enough resources to host all of them if one of the
nodes fails.
Additional Information:
===================
Introduction to Microsoft SQL Server 2000 Clustering
http://support.microsoft.com/default...lurb051001.asp
Microsoft SQL Server 2000 Virtual Server: Things You Should Know
http://support.microsoft.com/default...lurb032602.asp
Microsoft SQL Server 2000 Virtual Server Basic Setup, Maintenance, and Service Pack http://support.microsoft.com/default...lurb061002.asp
Microsoft SQL Server 2000 Failover Clustering Disaster Recovery Procedures
http://support.microsoft.com/default...lurb101802.asp
Troubleshooting SQL 2000 Virtual Server and Service Pack Setups for Failover Clustering
http://support.microsoft.com/default...lurb020703.asp
INF: Installation Order for SQL 2000 Enterprise Edition
http://support.microsoft.com/?kbid=243218
SQL Server 2000 Virtual Server Setup Error: "The Drive Chosen for the Program Files Installation Path <C:>, Is Not a Valid Path on All the Nodes of the Cluster"
http://support.microsoft.com/?id=279642
INF: Frequently Asked Questions - SQL Server 2000 - Failover Clustering
http://support.microsoft.com/?kbid=260758
HTH,
Best Regards,
Uttam Parui
Microsoft Corporation
This posting is provided "AS IS" with no warranties, and confers no rights.
Are you secure? For information about the Strategic Technology Protection Program and to order your FREE Security Tool Kit, please visit http://www.microsoft.com/security.
Microsoft highly recommends that users with Internet access update their Microsoft software to better protect against viruses and security vulnerabilities. The easiest way to do this is to visit the following websites:
http://www.microsoft.com/protect
http://www.microsoft.com/security/guidance/default.mspx
|||We have A/A SQL 2000 Clusters...from an administrative standpoint, A/A is
more to manage...the same principles as A/P apply, you just have more
resources ( drives for ach instance, ip's for each instance, etc.) Setting up
back ups to get the clustered drives can be a bit messy...you have to be able
to authenticate to your back up server as both nodes from both sides...what
if one node owns both instances? We do it every day though...read all you
can, then make it happen.
"Uttam Parui[MS]" wrote:

> Hi Rob,
> A/P and A/A terminology does not really apply for SQL Server 2000. It was used for SQL 7.0 clustering.
> * Single instance cluster: replaces an active/passive cluster. A single instance cluster means there is one SQL Server 2000 virtual server installed.
> * Multiple instance cluster: replaces an active/active cluster. A multiple instance cluster is one in which there is more than one SQL Server 2000 virtual server installed. Because of the way the implementation of
> clustering is different with SQL Server 2000, using the active/active terminology does not really apply. A multiple-instance cluster has up to four server nodes and supports up to 16 instances (1 default, 15 named or
> 16 named). Each SQL Server 2000 virtual server requires its own disk resources that cannot be used by other instances
> I would recommend you to review Microsoft SQL Server 2000 Failover Clustering whitepaper to get a clear picture
> Microsoft Whitepaper - SQL Server 2000 Failover Clustering
> http://www.microsoft.com/technet/pro.../failclus.mspx
> Although A/P and A/A are old terms, many still use it. For many, A/P means that there is just one instance of SQL Server 2000 running on the A node and nothing is running on P node. Many refer to A/A as first SQL
> Server instance running on first A node and second SQL Server instance running on second A node. This way both nodes are being used. This is used very commonly by customers. The IMPORTANT thing is
> that each node should have enough resources to host both the SQL Servers in case one node goes down. The above whitepaper has good scenarios and talks about how to configure the resources. A/P and
> A/A terms work ok till two instances. With SQL 2K, we can have upto 16 instances on a two node cluster. I have seen customers having four instances of SQL Server on a two node cluster. what will this be called
> now? So, its better to use that we have four instance SQL cluster on a two node windows MSCS. In case of a four instance SQL Cluster, each node should have enough resources to host all of them if one of the
> nodes fails.
> Additional Information:
> ===================
> Introduction to Microsoft SQL Server 2000 Clustering
> http://support.microsoft.com/default...lurb051001.asp
> Microsoft SQL Server 2000 Virtual Server: Things You Should Know
> http://support.microsoft.com/default...lurb032602.asp
>
> Microsoft SQL Server 2000 Virtual Server Basic Setup, Maintenance, and Service Pack http://support.microsoft.com/default...lurb061002.asp
> Microsoft SQL Server 2000 Failover Clustering Disaster Recovery Procedures
> http://support.microsoft.com/default...lurb101802.asp
> Troubleshooting SQL 2000 Virtual Server and Service Pack Setups for Failover Clustering
> http://support.microsoft.com/default...lurb020703.asp
> INF: Installation Order for SQL 2000 Enterprise Edition
> http://support.microsoft.com/?kbid=243218
> SQL Server 2000 Virtual Server Setup Error: "The Drive Chosen for the Program Files Installation Path <C:>, Is Not a Valid Path on All the Nodes of the Cluster"
> http://support.microsoft.com/?id=279642
> INF: Frequently Asked Questions - SQL Server 2000 - Failover Clustering
> http://support.microsoft.com/?kbid=260758
> HTH,
> Best Regards,
> Uttam Parui
> Microsoft Corporation
> This posting is provided "AS IS" with no warranties, and confers no rights.
> Are you secure? For information about the Strategic Technology Protection Program and to order your FREE Security Tool Kit, please visit http://www.microsoft.com/security.
> Microsoft highly recommends that users with Internet access update their Microsoft software to better protect against viruses and security vulnerabilities. The easiest way to do this is to visit the following websites:
> http://www.microsoft.com/protect
> http://www.microsoft.com/security/guidance/default.mspx
>
>

A few questions: Clustering & Replication

Hi,
In SQL 2005, with SQL Clustering:
1. Can a THREE-node active/active/active cluster be setup? If yes, is
setting up a three-node a/a/a cluster recommended? Any pitfalls or gotchas
that one needs to be aware of?
With Replication:
1. Can a subscriber in turn be a publisher to another subscriber? i.e. a
subscriber subsribes to a publication from one publisher and then in turn
creates a similar publication, which is subscribed by another subscriber.
2. Can replication (immediate and/or queued updating) be configured between
THREE servers? i.e. each server is a publisher and subcriber to the other two
servers.
We are working on a global strategy to identify how best to keep data in
sync between three geographically located SQL servers, while maintaining
latency as low as possible.
Peer-to-Peer replication was investigated as well, but it did not fit with
our company's strategic plan as one of our requirement is that database
updates can be done at any server, at anytime. Peer-to-Peer allows updates
for a given row only at one database until it has been syncronized with its
peers, which can be done by directing updates for a set of rows to a
particular server.
Your guidance, thougths, and suggestions are very valued and appreciated.
TIA
Regards,<DIV>"Rob" <Rob@.discussions.microsoft.com> wrote in message
news:7C72EA17-1D74-42FA-BA28-6A0CBDC5535C@.microsoft.com...</DIV>> Hi,
> In SQL 2005, with SQL Clustering:
> 1. Can a THREE-node active/active/active cluster be setup? If yes, is
> setting up a three-node a/a/a cluster recommended? Any pitfalls or gotchas
> that one needs to be aware of?
Yes, although we don't really call it active/active anymore. It's just an
N-node cluster. It has a number of cluster nodes and a number of SQL
instances (virtual servers). The biggest problem with running SQL instances
on all your cluster nodes is that you can have performance problems when you
fail over. Often you add an extra passive node to hold enough capacity in
reserve for failover. This is generally referred to as an N+1 cluster (N
"active" nodes, 1 "passive").
> With Replication:
> 1. Can a subscriber in turn be a publisher to another subscriber? i.e. a
> subscriber subsribes to a publication from one publisher and then in turn
> creates a similar publication, which is subscribed by another subscriber.
> 2. Can replication (immediate and/or queued updating) be configured
> between
> THREE servers? i.e. each server is a publisher and subcriber to the other
> two
> servers.
> We are working on a global strategy to identify how best to keep data in
> sync between three geographically located SQL servers, while maintaining
> latency as low as possible.
> Peer-to-Peer replication was investigated as well, but it did not fit with
> our company's strategic plan as one of our requirement is that database
> updates can be done at any server, at anytime. Peer-to-Peer allows updates
> for a given row only at one database until it has been syncronized with
> its
> peers, which can be done by directing updates for a set of rows to a
> particular server.
You've got it wrong with Peer-to-Peer. Peer-to-Peer allows update to any
server at anytime. It just has no mechanism to protect you if you make
conflicting changes at nearly the same time, one of the changes will be
lost. The situation you are describing with multiple publishers would
behave in a similar manner.
David|||1) Yes, the gotcha is that at any one time a node may have to support all
three instances which means it will have to be pretty beefy to offer optimal
performance to all three instances
Replication
1) Yes, its called republishing. It normally used to provide hierarchies in
merge replication to scale out.
2) No, but you might want to look at bi-directional transactional
replication which can be used to do this. It would provide bi-directional
replication between node a and node b, and node a and node c, but not
between node b and node c unless you implement some pretty complex
filtering.
When Peer to peer out of the box encounters an error its distribution agents
will stop until you fix the error. You can run it in the continue on data
consistency errors profile, but doing this will leave your databases in an
inconsistent state.
--
Hilary Cotter
Director of Text Mining and Database Strategy
RelevantNOISE.Com - Dedicated to mining blogs for business intelligence.
This posting is my own and doesn't necessarily represent RelevantNoise's
positions, strategies or opinions.
Looking for a SQL Server replication book?
http://www.nwsu.com/0974973602.html
Looking for a FAQ on Indexing Services/SQL FTS
http://www.indexserverfaq.com
"Rob" <Rob@.discussions.microsoft.com> wrote in message
news:7C72EA17-1D74-42FA-BA28-6A0CBDC5535C@.microsoft.com...
> Hi,
> In SQL 2005, with SQL Clustering:
> 1. Can a THREE-node active/active/active cluster be setup? If yes, is
> setting up a three-node a/a/a cluster recommended? Any pitfalls or gotchas
> that one needs to be aware of?
> With Replication:
> 1. Can a subscriber in turn be a publisher to another subscriber? i.e. a
> subscriber subsribes to a publication from one publisher and then in turn
> creates a similar publication, which is subscribed by another subscriber.
> 2. Can replication (immediate and/or queued updating) be configured
> between
> THREE servers? i.e. each server is a publisher and subcriber to the other
> two
> servers.
> We are working on a global strategy to identify how best to keep data in
> sync between three geographically located SQL servers, while maintaining
> latency as low as possible.
> Peer-to-Peer replication was investigated as well, but it did not fit with
> our company's strategic plan as one of our requirement is that database
> updates can be done at any server, at anytime. Peer-to-Peer allows updates
> for a given row only at one database until it has been syncronized with
> its
> peers, which can be done by directing updates for a set of rows to a
> particular server.
> Your guidance, thougths, and suggestions are very valued and appreciated.
> TIA
> Regards,|||Hi Rob,
the only thing I'd add to the other comments is that merge replication
essentially covers point (2). The terminology is in conflict but the
functionality is the same ie there would only be need for one publisher, and
the pthers would be subscribers, but for the most part, there isn't a
distinction between these roles in merge replication.
Cheers,
Paul Ibison SQL Server MVP, www.replicationanswers.com|||Thanks Hilary.
For replication Q. 2: You may have already answered this but I was wondering
if a bi-directional replication were to exists between node A and B, could
node B republish the data to node C unidirectionally?
Regards,
- Rob.
"Hilary Cotter" wrote:
> 1) Yes, the gotcha is that at any one time a node may have to support all
> three instances which means it will have to be pretty beefy to offer optimal
> performance to all three instances
> Replication
> 1) Yes, its called republishing. It normally used to provide hierarchies in
> merge replication to scale out.
> 2) No, but you might want to look at bi-directional transactional
> replication which can be used to do this. It would provide bi-directional
> replication between node a and node b, and node a and node c, but not
> between node b and node c unless you implement some pretty complex
> filtering.
> When Peer to peer out of the box encounters an error its distribution agents
> will stop until you fix the error. You can run it in the continue on data
> consistency errors profile, but doing this will leave your databases in an
> inconsistent state.
> --
> Hilary Cotter
> Director of Text Mining and Database Strategy
> RelevantNOISE.Com - Dedicated to mining blogs for business intelligence.
> This posting is my own and doesn't necessarily represent RelevantNoise's
> positions, strategies or opinions.
> Looking for a SQL Server replication book?
> http://www.nwsu.com/0974973602.html
> Looking for a FAQ on Indexing Services/SQL FTS
> http://www.indexserverfaq.com
>
> "Rob" <Rob@.discussions.microsoft.com> wrote in message
> news:7C72EA17-1D74-42FA-BA28-6A0CBDC5535C@.microsoft.com...
> > Hi,
> >
> > In SQL 2005, with SQL Clustering:
> > 1. Can a THREE-node active/active/active cluster be setup? If yes, is
> > setting up a three-node a/a/a cluster recommended? Any pitfalls or gotchas
> > that one needs to be aware of?
> >
> > With Replication:
> > 1. Can a subscriber in turn be a publisher to another subscriber? i.e. a
> > subscriber subsribes to a publication from one publisher and then in turn
> > creates a similar publication, which is subscribed by another subscriber.
> > 2. Can replication (immediate and/or queued updating) be configured
> > between
> > THREE servers? i.e. each server is a publisher and subcriber to the other
> > two
> > servers.
> >
> > We are working on a global strategy to identify how best to keep data in
> > sync between three geographically located SQL servers, while maintaining
> > latency as low as possible.
> >
> > Peer-to-Peer replication was investigated as well, but it did not fit with
> > our company's strategic plan as one of our requirement is that database
> > updates can be done at any server, at anytime. Peer-to-Peer allows updates
> > for a given row only at one database until it has been syncronized with
> > its
> > peers, which can be done by directing updates for a set of rows to a
> > particular server.
> >
> > Your guidance, thougths, and suggestions are very valued and appreciated.
> >
> > TIA
> >
> > Regards,
>
>

A few questions: Clustering & Replication

Hi,
In SQL 2005, with SQL Clustering:
1. Can a THREE-node active/active/active cluster be setup? If yes, is
setting up a three-node a/a/a cluster recommended? Any pitfalls or gotchas
that one needs to be aware of?
With Replication:
1. Can a subscriber in turn be a publisher to another subscriber? i.e. a
subscriber subsribes to a publication from one publisher and then in turn
creates a similar publication, which is subscribed by another subscriber.
2. Can replication (immediate and/or queued updating) be configured between
THREE servers? i.e. each server is a publisher and subcriber to the other tw
o
servers.
We are working on a global strategy to identify how best to keep data in
sync between three geographically located SQL servers, while maintaining
latency as low as possible.
Peer-to-Peer replication was investigated as well, but it did not fit with
our company's strategic plan as one of our requirement is that database
updates can be done at any server, at anytime. Peer-to-Peer allows updates
for a given row only at one database until it has been syncronized with its
peers, which can be done by directing updates for a set of rows to a
particular server.
Your guidance, thougths, and suggestions are very valued and appreciated.
TIA
Regards,<DIV>"Rob" <Rob@.discussions.microsoft.com> wrote in message
news:7C72EA17-1D74-42FA-BA28-6A0CBDC5535C@.microsoft.com...</DIV>> Hi,
> In SQL 2005, with SQL Clustering:
> 1. Can a THREE-node active/active/active cluster be setup? If yes, is
> setting up a three-node a/a/a cluster recommended? Any pitfalls or gotchas
> that one needs to be aware of?
Yes, although we don't really call it active/active anymore. It's just an
N-node cluster. It has a number of cluster nodes and a number of SQL
instances (virtual servers). The biggest problem with running SQL instances
on all your cluster nodes is that you can have performance problems when you
fail over. Often you add an extra passive node to hold enough capacity in
reserve for failover. This is generally referred to as an N+1 cluster (N
"active" nodes, 1 "passive").

> With Replication:
> 1. Can a subscriber in turn be a publisher to another subscriber? i.e. a
> subscriber subsribes to a publication from one publisher and then in turn
> creates a similar publication, which is subscribed by another subscriber.
> 2. Can replication (immediate and/or queued updating) be configured
> between
> THREE servers? i.e. each server is a publisher and subcriber to the other
> two
> servers.
> We are working on a global strategy to identify how best to keep data in
> sync between three geographically located SQL servers, while maintaining
> latency as low as possible.
> Peer-to-Peer replication was investigated as well, but it did not fit with
> our company's strategic plan as one of our requirement is that database
> updates can be done at any server, at anytime. Peer-to-Peer allows updates
> for a given row only at one database until it has been syncronized with
> its
> peers, which can be done by directing updates for a set of rows to a
> particular server.
You've got it wrong with Peer-to-Peer. Peer-to-Peer allows update to any
server at anytime. It just has no mechanism to protect you if you make
conflicting changes at nearly the same time, one of the changes will be
lost. The situation you are describing with multiple publishers would
behave in a similar manner.
David|||1) Yes, the gotcha is that at any one time a node may have to support all
three instances which means it will have to be pretty beefy to offer optimal
performance to all three instances
Replication
1) Yes, its called republishing. It normally used to provide hierarchies in
merge replication to scale out.
2) No, but you might want to look at bi-directional transactional
replication which can be used to do this. It would provide bi-directional
replication between node a and node b, and node a and node c, but not
between node b and node c unless you implement some pretty complex
filtering.
When Peer to peer out of the box encounters an error its distribution agents
will stop until you fix the error. You can run it in the continue on data
consistency errors profile, but doing this will leave your databases in an
inconsistent state.
Hilary Cotter
Director of Text Mining and Database Strategy
RelevantNOISE.Com - Dedicated to mining blogs for business intelligence.
This posting is my own and doesn't necessarily represent RelevantNoise's
positions, strategies or opinions.
Looking for a SQL Server replication book?
http://www.nwsu.com/0974973602.html
Looking for a FAQ on Indexing Services/SQL FTS
http://www.indexserverfaq.com
"Rob" <Rob@.discussions.microsoft.com> wrote in message
news:7C72EA17-1D74-42FA-BA28-6A0CBDC5535C@.microsoft.com...
> Hi,
> In SQL 2005, with SQL Clustering:
> 1. Can a THREE-node active/active/active cluster be setup? If yes, is
> setting up a three-node a/a/a cluster recommended? Any pitfalls or gotchas
> that one needs to be aware of?
> With Replication:
> 1. Can a subscriber in turn be a publisher to another subscriber? i.e. a
> subscriber subsribes to a publication from one publisher and then in turn
> creates a similar publication, which is subscribed by another subscriber.
> 2. Can replication (immediate and/or queued updating) be configured
> between
> THREE servers? i.e. each server is a publisher and subcriber to the other
> two
> servers.
> We are working on a global strategy to identify how best to keep data in
> sync between three geographically located SQL servers, while maintaining
> latency as low as possible.
> Peer-to-Peer replication was investigated as well, but it did not fit with
> our company's strategic plan as one of our requirement is that database
> updates can be done at any server, at anytime. Peer-to-Peer allows updates
> for a given row only at one database until it has been syncronized with
> its
> peers, which can be done by directing updates for a set of rows to a
> particular server.
> Your guidance, thougths, and suggestions are very valued and appreciated.
> TIA
> Regards,|||Hi Rob,
the only thing I'd add to the other comments is that merge replication
essentially covers point (2). The terminology is in conflict but the
functionality is the same ie there would only be need for one publisher, and
the pthers would be subscribers, but for the most part, there isn't a
distinction between these roles in merge replication.
Cheers,
Paul Ibison SQL Server MVP, www.replicationanswers.com|||Thanks Hilary.
For replication Q. 2: You may have already answered this but I was wondering
if a bi-directional replication were to exists between node A and B, could
node B republish the data to node C unidirectionally?
Regards,
- Rob.
"Hilary Cotter" wrote:

> 1) Yes, the gotcha is that at any one time a node may have to support all
> three instances which means it will have to be pretty beefy to offer optim
al
> performance to all three instances
> Replication
> 1) Yes, its called republishing. It normally used to provide hierarchies i
n
> merge replication to scale out.
> 2) No, but you might want to look at bi-directional transactional
> replication which can be used to do this. It would provide bi-directional
> replication between node a and node b, and node a and node c, but not
> between node b and node c unless you implement some pretty complex
> filtering.
> When Peer to peer out of the box encounters an error its distribution agen
ts
> will stop until you fix the error. You can run it in the continue on data
> consistency errors profile, but doing this will leave your databases in an
> inconsistent state.
> --
> Hilary Cotter
> Director of Text Mining and Database Strategy
> RelevantNOISE.Com - Dedicated to mining blogs for business intelligence.
> This posting is my own and doesn't necessarily represent RelevantNoise's
> positions, strategies or opinions.
> Looking for a SQL Server replication book?
> http://www.nwsu.com/0974973602.html
> Looking for a FAQ on Indexing Services/SQL FTS
> http://www.indexserverfaq.com
>
> "Rob" <Rob@.discussions.microsoft.com> wrote in message
> news:7C72EA17-1D74-42FA-BA28-6A0CBDC5535C@.microsoft.com...
>
>