VCS mount question

[mokkan]

Hello,

I have got the following request. and let me know is there a way I can setup.

I  need to setup a  SQL server  on Windows 2008 and data will be on RDM1. Also, there will be another RDM2. Some times customer wants to start the SQL with RDM1 and some times they want to start with RDM2.

Can I setup a SG with IP. mount, SQLserver,  RDM1? And create another SG just for RDM2 for mount the Drive? 

[mikebounds]

Not quite sure what you are asking - I think you want:

SQL1 in SG1 using LUN1 (RDM LUN)

SQL2 in SG2 using LUN2 (RDM LUN)

This is fine if SQL1 and SQL2 have different instance names, but if they have the same instance name then you will probably get concurrency violations in VCS, but you may be able to get round this by setting the Firedrill attribute on the SQLServer Type and you would probably also want to use System Limits and Group Prereqs to prevent both SGs starting on the same server.

If this is what you are trying to do with SG1 and SG2 with the same SQL instance name, then I can post more details on using Firedrill attribute and System Limits and Group Prereqs.

Mike

[mokkan]

Thank you Mike. Sorry I didn't provide all the info.   RDM1 and RDM2 will have same data and we will have one database instance. If customer asks us to start the database using RDM1, we need to start using RDM1, but if customer wants to start the database using RDM2, we need to start the database using RDM2. Is it possible?

It doesn't make any sense, but this is the customer requirment.

[Wally_Heim]

Hi Mokkan,

I'm not sure that I understand the exact reason/need for this in a production environment.  But what you are asking sounds to me like you would need to reconfigure the service group to get the needed RDM disk/volume in the right location for SQL to use. 

I'm sure that you could script the changes needed but the exact changes needed would be depend on the disk/diskgroup configuration that you are using.  I would try to keep the change down to just modifying 1 or 2 Mount/MountV resources.  The simipler the change the less likely you are to mess it up.

Can you please go into more details on what you are trying to do by changing the drive/data that SQL is using?  Maybe there is something else that we can recommend that might work better for you situation.

Thank you,

Wally

[mokkan]

This is my plan, if I am wrong correct me.

Create 2 SGs, one SG for RDM1 with drive G and another SG with RDM2 with drive G and setup database intance.

only difference between these SGs are VG and Mount, rest of them are same.

Setup SG1 as auto stat, and SG2 will start only when we manually bring online. Would it work?

[mokkan]

This host is the DR server and will have 2 RDMs, one will use during the DR, other RDM will be used during the test. Time to time DATA will be copied form Real RM to the test RDM.  Customer wants to launch the database using RDM1 or RDM2, it all depends on the situation.

I was thinking to create 2 SGs with same info except VG and  Volume, but  mount point will be same. IF they want launch the DB from RDM2, bring offline the SG1, and online the SG2 which will have RDM2. Would it work?

[Wally_Heim]

Hi Mokkan,

The 2 service group approach will cause problems with each other without setting one up as a FireDrill service group.  If you are going to have to do the FireDrill settings manually, then why not just use the FireDrill wizard to handle setting up the second service group with the needed FireDrill attributes.

FireDrill works off of a snapshot copy of the data being replicated to the DR site.  The wizard will snap the volumes, split the diskgroup and start the FireDrill service gruop with the snapshot copy of the data.  It will also change the virtual server name and other attributes as need to not interfer with the DR service group.  The good thing about using the FireDrill in this way is that you can refresh the data with the wizard and the snapshot will resync quicker than a standard data copy would.

In your case, the snapshot would be done with RDM2 and the production data being replicated to RDM1.

Check out the manuals for FireDrill for more details.

Thank you,

Wally

[mokkan]

Thank you very much, the problem is that customer has their own method to copy the data using IBM SAN and they are using flash copy to the data.  What kind of problem I will would if I setup SG for same DB using different LUN? I will only mount after other SG is offline.

[Wally_Heim · Accepted solution]

Hi Mokkan,

Check out the FireDrill in the docs.  It should cover the ForFireDrill attribute in the VMDg and MountV resources. The other things that you will need to be concerned with is that the second service group will need a different IP and Lanman virtual server name so that it does not cause problems with the production SQL instance.

The SQL server resource and GenericService resources should be OK since they should be using the virtual server name and can determine that SQL Server and SQL Agent services are running in a different virtual server context.  But you might want to be careful when you do your first test online of the second service group.

Thank you,

Wally