NAV Licensing for Cluster Enviroment

Soumyadip

I was going through PartnerSource documents and licensing explanation but would request your help to understand the licensing requirement/behaviour under the following scenario -

In an imaginary scenario as follows –
• Customer wants NAV 2009
• Customer needs 20 Concurrent and 50 Named users
• Customer wants to explore options of High Availability + Load Balancing

NAV License Requirement -

1) Non-Cluster
• SQL Server = 1 (Standard Edition)
• SQL CAL = 50
• NAV = 20 CAL + 1 Dynamics NAV Server + Other standard components(like AM or BE foundation + objects + functional features etc)

2) Active - Passive Cluster
• SQL Server = 2 (Enterprise Edition)
• SQL CAL = 50
• NAV = ?

3) Active - Active Cluster
• SQL Server = 2 (Enterprise Edition)
• SQL CAL = 50
• NAV = ?

Please let me know if my understanding about SQL licensing under scenario 2 and 3 are right...and what would be the corresponding NAV license requirement.

Thanks.

kine

Because NAV is not supporting clustering in any way (I am not talking about SQL clustering), there is no special need for the NAV license. There is no load balancing in the NAV 2009. You will need to solve this in some way (e.g. by som application launching the client which will change client configuration in a way that it will select which server the RTC will connect).

Soumyadip

So the best solution is -

1. Cluster NAV SQL DB Server (either AA or AP)
2. Put NAV Server in two boxes one active another dead/idle

During disaster -
If SQL Box goes down
1. SQL cluster will automaticaly take care and will follow the standard cluster procedure
2. Nothing to be done for NAV Server and NAV Client

IF NAV Server goes down
1. Bring up the dead/idle NAV Server box
2. Change the client config (either manually or via some automation) so that now it connects to the other NAV Server box.

As the 2nd NAV server is dead/idle no additional license is required.

Am i right in my understanding?

kine

For me it seems correct. But I am not so experienced in the licensing...

David_Singleton

Why do you want to cluster the SQL server?

kine

To have NAV available even when the used HW fail (CPU, RAM, Motherboard, PowerSupply).

David_Singleton

kine wrote:

To have NAV available even when the used HW fail (CPU, RAM, Motherboard, PowerSupply).

How will clustering the SQL server achieve that? The issue remains that the Navision server is not clustered and has no fail over.

kine

Yes, but it is on different HW and fail of this HW is solved in another way, just read the post... ;-)

David_Singleton

kine wrote:

Yes, but it is on different HW and fail of this HW is solved in another way, just read the post... ;-)

I read the post. My question was "how does clustering help?"

David_Singleton

kine wrote:

Yes, but it is on different HW and fail of this HW is solved in another way, just read the post... ;-)

I read the post. My question was "how does clustering help?"

kine

How? Like any other cluster... I do not know what is the problem...

If one server in cluster goes down, you have still NAV DB available and you can use the system (Fail of HDD is solved on RAID level).

If you do not have cluster, you need to repair the server to be able to use the system...

David_Singleton

It just reminds me of this...

David_Singleton

Or this

kine

Yes, but you have smaller probability of unavailability, do not forget about that... ;-)

David_Singleton

kine wrote:

Yes, but you have smaller probability of unavailability, do not forget about that... ;-)

Yes in theory, but in practice does it make sense. Lets take the case above.

Lets say we are worried about someone stealing the barbeque in our front yard. Then we need to address the fact that a/ There needs to be a thief, b/ The thief needs opportunity and motive, c/ The thief needs to be able to break into the house. So assuming a and b, lets look at C.

A thief has many ways of getting into the yard. i/ They can get a helicopter and use a rope to lower them selves into the yard, ii/ They can go through the green steel gate, iii/ they can jump the hedge. (There are of course many more options, but lets look at these).

SO the probabilities for each are
1/ The thief must have access to a helicopter and know how to use it (or some one that does to get over the fence) Lets say the odds of that are 1,000,000:1.
ii/ To open the gate, the thief must know the gate is a possible egress and also know how to open the gate. Lets say that there is a 10:1 chance that the thief has the ability to open the lock or break the lock. And a 10:9 chance they know that the gate is an egress, giving us a 9% chance of access through that route.
iii/ lets say the chance that a thief knows that they can get in via the hedge is 99% and the ability to jump the hedge is 99.9% giving a 98.9% chance.

The point now is that theory shows that if we spend money to fix up the lock on the gate, we might make the chances of a thief being able to open the gate drop from 9% to 1%. But in reality we know that the big issue is the hedge. Thus its better to spend the money building a solid wall that buying a better lock.

I know that this is all silly, but the point is that the Clustered server adds no additional security, since the ONLY reason you would use a cluster is for automated roll over. IN this case someone still has to manually switch the Navision server over, so there is no advantage.

kine

No, you do not need to reconnect NST manually, the cluster itself will move your existing connections and unfinished transactions to the second server in the cluster... that's the point... Te cluster have one IP for others, which is automatically forwarded to network of server1 or server2 and the connections are shifted to the live server automatically, and because the SQL is in cluster mode with shared disc, the transaction log is keeping your unfinished transactions during the reconnect.

David_Singleton

You have miss read my posts. My comment is that unless THE WHOLE SYSTEM is redundant and reliable, it makes no sense to fix just one part of the system.

In the scenario that the Navision Server (NST) has one active and one standby server, then if the primary fails, its necessary to start the idle server, connect it to SQL and then tell the users to log in to the new server. This is not automated without clustering. And you read above that the plan is to cluster only the SQL server, thus my first question.

kine

Yes, but this is only "IF NST HW fail". But if "SQL HW fail" is not problem, and still it is better than have both on off-line solution... ;-)

David_Singleton

kine wrote:

Yes, but this is only "IF NST HW fail". But if "SQL HW fail" is not problem, and still it is better than have both on off-line solution... ;-)

I disagree.

Please take a look at the pictures I posted above to understand why.

kine

Problem is, that your "example" is based on one thing - that the "attacker" is inteligent, but HW failure is not inteligent... it will not automatically "select" that the fail will be on the weaker HW, which is not in cluster... ;-)

bbrown

Licensing can vary depending on how Windows and SQL is acquired. Licensing rights can vary between retail, OEM, and Volume Purchase agreements. WIth VPA, SQL 2008 does not need to be licensed if it is a passive server. But there are time limits if you fail over to it, after which it must be licensed.

See http://www.microsoft.com/sqlserver/2008/en/us/licensing.aspx from more info

Soumyadip

I think i will be able to minimize the risk of outage in my proposed approach. Here, I have two possible outage points.

1) NAV Server - I am keeping another server with same configuration ready. So during outage i can quickly turn it on/put it on network and change my NAV client config to bring the system back. Yes, it is not full proof but i do have a good RTO (Recovery Time Objective) of around 30mins.

2) SQL Server - If SQL Server is clustered then it would auto fall back to the other server during outage. So, I do not have to worry about it.

It is true that even i do not have issues with SQL but NAV server would not let me give a better SLA than of RTO = 30min ... but the chances of outage would be reduced by 50%

What do you guys think?

Thanks for pointing to SQL licensing in cluster mode installation. Something i would like to reconfirm, in the above mentioned solution, as one of the NAV server is always idle/dead... I do not need any additional license apart from the simple license that would be required in a non-clustered deployment.

I think i have seen some document in PartnerSource sometime back "Navision 4 0 on MS Cluster Server"... that talks about NAV clustering.

I am wondering why NAV 2009 has taken a step backward in this area... (Kine mentioned..NAV 2009 do not support cluster) .... Any idea?

bbrown

No version of NAV has ever supported clustering. That is they have never been cluster-aware. There is a difference between "instructions to install on a cluster" and "being cluster-aware"

bbrown

Don't assume that clustering will protect you from any failure scenario of SQL. Clsutering is meant to protect the operating evvironment, not the database. We had a customer, with a cluster, that still went down because the shared disk array failed.

You might consider database mirroring in high availability mode as an option. I like this option as it opens up a broader choice of hardware. But, unlike clustering, it protects the database and not the operating environment.

Soumyadip

Yup... NAV do not understand cluster automatically, it is not cluster aware as SQL server is and we need to manually configure the services in cluster.

But, Does it auto fall back to the passive node once it encounter issues in active node?

Agree..SQL cluster do not give 100% protection...and other better options are available like log shipping and mirroring...

bbrown

Soumyadip wrote:

But, Does it auto fall back to the passive node once it encounter issues in active node?

Not sure if you are asking about clustering or mirroring. With Mirroring, it depends on the operating mode. With High Availability mode, the answer is yes.

Clustering swithes to another server instance that is pointing to the same database. Mirroring provides a second server that is running a second (mirrored) copy of the database.

Soumyadip

thanks... but here I am talking about NAV...

1. Does NAV support cluster? ... i know it is not cluster aware but it seems that it can be deployed in clustered mode. In cluster mode will it auto fall back to the passive server?

2. If it can be deployed in cluster (Active-Passive)...what NAV licensing would be required? Can I assume no additional license is required as in a given time only a single node is active? ..hence i can go for the same pricesheet configuration as i would have gone in a non-clustered enviroment...

3. is it possible to deploy NAV 2009 in Active-Active cluster? does it do Load Ballancing? What additional NAV license would be required?

bbrown

Soumyadip wrote:

thanks... but here I am talking about NAV...

1. Does NAV support cluster? ... i know it is not cluster aware but it seems that it can be deployed in clustered mode. In cluster mode will it auto fall back to the passive server?

2. If it can be deployed in cluster (Active-Passive)...what NAV licensing would be required? Can I assume no additional license is required as in a given time only a single node is active? ..hence i can go for the same pricesheet configuration as i would have gone in a non-clustered enviroment...

3. is it possible to deploy NAV 2009 in Active-Active cluster? does it do Load Ballancing? What additional NAV license would be required?

You would not be deploying NAV in the cluster, you would be deploying SQL, so NAV is irrelevant.

Soumyadip

Soumyadip wrote:

I think i will be able to minimize the risk of outage in my proposed approach. Here, I have two possible outage points.

1) NAV Server - I am keeping another server with same configuration ready. So during outage i can quickly turn it on/put it on network and change my NAV client config to bring the system back. Yes, it is not full proof but i do have a good RTO (Recovery Time Objective) of around 30mins.

2) SQL Server - If SQL Server is clustered then it would auto fall back to the other server during outage. So, I do not have to worry about it.

In this scenario ..obviously i would not be deploying NAV in cluster...

But question is... for the idle/dead node with pre-configured NAV...do i need license?

Now the 2nd part...

We do have a document available in partner source depicting NAV cluster...

now the questions for 2nd part -

1. Does NAV support cluster? ... i know it is not cluster aware but it seems that it can be deployed in clustered mode. In cluster mode will it auto fall back to the passive server?

2. If it can be deployed in cluster (Active-Passive)...what NAV licensing would be required? Can I assume no additional license is required as in a given time only a single node is active? ..hence i can go for the same pricesheet configuration as i would have gone in a non-clustered enviroment...

3. is it possible to deploy NAV 2009 in Active-Active cluster? does it do Load Ballancing? What additional NAV license would be required?

bbrown

Soumyadip wrote:

Soumyadip wrote:

I think i will be able to minimize the risk of outage in my proposed approach. Here, I have two possible outage points.

1) NAV Server - I am keeping another server with same configuration ready. So during outage i can quickly turn it on/put it on network and change my NAV client config to bring the system back. Yes, it is not full proof but i do have a good RTO (Recovery Time Objective) of around 30mins.

2) SQL Server - If SQL Server is clustered then it would auto fall back to the other server during outage. So, I do not have to worry about it.

In this scenario ..obviously i would not be deploying NAV in cluster...

But question is... for the idle/dead node with pre-configured NAV...do i need license?

Now the 2nd part...

We do have a document available in partner source depicting NAV cluster...

now the questions for 2nd part -

1. Does NAV support cluster? ... i know it is not cluster aware but it seems that it can be deployed in clustered mode. In cluster mode will it auto fall back to the passive server?

2. If it can be deployed in cluster (Active-Passive)...what NAV licensing would be required? Can I assume no additional license is required as in a given time only a single node is active? ..hence i can go for the same pricesheet configuration as i would have gone in a non-clustered enviroment...

3. is it possible to deploy NAV 2009 in Active-Active cluster? does it do Load Ballancing? What additional NAV license would be required?

NAV licensing is not impacted by a cluster. You need to license the NAV users the same, regardless of whether or not the server is in a cluster.

NAV does not supprt auto-failover, in either direction.

And Active-Active cluster is not about load-balancing, with any application.

Soumyadip

NAV licensing is not impacted by a cluster. You need to license the NAV users the same, regardless of whether or not the server is in a cluster.

That resolves the basic intention of my post.

NAV does not supprt auto-failover, in either direction.

I am not 100% sure, but the NAV cluster document for version 4.0 gives me a feeling that it performs a auto-faliover. Once the active server is down, automatically the passive server comes online. The manual activity required, is to close the client and re-connect again (it even reconnects automaticaly if idle for ~10mins) ...
Any comments on this?

And Active-Active cluster is not about load-balancing, with any application

Thats a bad statement .. my appologies #-o