Friday, March 30, 2012

Mirroring between Standard and Enterprise editions...

Hi All,

We are going to use database mirroring and database snapshots for reporting. The principal server runs SQL Server 2005 Standard Edition and mirror (reporting) runs SQL Server 2005 Enterprise Edition (64-bit). I failed to setup database mirroring trough GUI using SQL Server Management Studio and got this error:

This mirroring configuration is not supported. Because the principal server instance, <server_name>, is Standard Edition, the mirror server instance must also be Standard Edition.

But when I use T-SQL commands I was able to setup database mirroring and it works OK so far.

SQL BOL says that one of requirements for database mirroring is to use the same SQL Server editions but I am wondering if it works trough T-SQL why MS mention it in the requirements list, also is totally unsupported by MS?

Thanks

Oleg

Oleg,

While this will probably work fine, we don't test this combination internally. If you mirror from a principal that is STD edition to a mirror that is EE edition, it would probably work without issues. Mirroring the other way (from EE to STD) could be problematic because of the EE features that are not present in STD. Since mirroring supports failover and failback, in theory it is possible for you to be in the situation where you are mirroring from EE->STD edition even if that is not the initial configuarion.

Regards,

Matt Hollingsworth

Program Manager, SQL Server High Availability

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Matt,

Thanks for your answer.

Our plan is to use database mirroring only for reporting and not for high availability. (We use replication and remote DC for HA). So mirroring from Standard to Enterprise Edition will be the only one scenario that we going to use option in our reporting environment.
The concern that we have is if we will be able to use mirroring between Standard and Enterprise in the future releases of SP2, SP3.

Thanks Oleg

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I am curious to why you want EE on the mirror server?

Only because the database snapshot feature?

Actually this is very similiar to what we need (use mirroring mostly for reports, not for HA) but since we don't have EE, we actually setup 2 STD instances on the mirror server

Server1 <- live server

Server2\Mirror <- mirrored, can be automatic fail over

Server2\Log <- log shipping, used for reports

Server3 <- witness and log shipping monitor server

Although I do recall seeing someone mention that we do not need a license if only using the mirror server in standby mode

Does that mean we can use EE with snapshot on Server2 without having to pay a license?

Thanks

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Yes we are going to use EE edition only for reporting since it doesn't require extra support efforts and also we can have a fair data refresh latency.
For the stand-by server you don't have to pay for licensing and it's valid for cluster or mirroring unless you also going to use it also for reporting.

tnx.

I'm closing this topic, thanks to all for answers and inputs............OH

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>> Although I do recall seeing someone mention that we do not need a license if only using the mirror server in standby mode

No, it doesn't. This only applies if you are using the 2nd server for failover only. By creating snapshots and running reporting off of it, it is no longer a failover only server.

Also, in order to cover both servers under 1 license, the license has to be valid for each server. So, you would have to run both under an Enterprise license, not a standard license.

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