Disaster recovery system on MSSQL 2005 / ECC 5.0

[Former Member]

Hello guys,

We are planning to have a DR system which would stand as our production system which is ECC 5.0 on MSSQL 2005. The DB team says they can get the database real time replication done via mirroring. I believe this allows transaction logs to be shipped in real time keeping the DR box in synch with the change on the production system.

1) Let us say the productrion SID is PRD. Would we have any issues if we have 2 hosts with the same SID = PRD connected via a network to each other (albeit both will be in different data centers) ?

If we install a different SID we would have an issue with the schema and would require conversion as we do post system refresh, would that not be the case ?

2) Could we keep the same instance number for the DR PRD ? Would it not have to be the same for service sapmsPRD to work?

3) The hosts in this case have to be different. In this case, how would the logon groups config on the saplogon re-reoute to the right ip ? . How will the saplogon.ini be affected ?

4) What will need to be done if we need the switch over to be automatic and not manual. That is primary goes down and DR standy senses this and comes up ? . Is this supported in the MSSQL2005 via mirroring and what config in SAP is required to make this work ?

Appreaciate any help on this and if you could guide me to some documents specifically related to MSSQL db

Thanks in advance, Vikram

[Former Member · Accepted solution]

I would suggest you to follow the homogeneous system copy procedures.

http://service.sap.com/systemcopy

[Former Member · Accepted solution]

Manoj,

I am sorry if I was not clearer in my previous post. We are not wanting a system copy. The db at DR site is going to be in synch via replication. Besides, there should not a significant amount of gap between the time the primary goes down and the standy by is online for productive use. When the primary goes down, we do not have the time to do a system copy to standby and then perform post processing to provide a refreshed system to users. The expectation is that there is hardly any time lag between the failure of the primary and the take over of the secondary. My above questions were specific to a DR scenario. An exact replica of the primary in terms of SID and database updates (with all the latest data as was posted upto the point of failure on primary) has to be up and running on secondary site within may be 5 to 10 mins at most from the time of failure of the primary.

regards, Vikram

[Former Member]

Hi,

You can go with the DR server with the same SID(PRD) as the host you are using for the DR server is different.

But did you confirm from the Database team that how are ther going to Sink the Database.

Thanks

Rishi Abrol

[Former Member]

Thanks Rishi, the DB team is going to use MSSQL2005 mirroring. The note that Nikunj furnishes above gives a lot of details on this.

Thanks Nikunj, that note really is very helpful. It is THE note for our case. Thanks !!!

I am keeping this thread open since we will be doing this over the next week...I'll reach out if we have any issues.

regards, Vikram

[Former Member]

> 1) Let us say the productrion SID is PRD. Would we have any issues if we have 2 hosts with the same SID = PRD connected via a network to each other (albeit both will be in different data centers) ?

No issue you have to keep Database SID same.

> 2) Could we keep the same instance number for the DR PRD ? Would it not have to be the same for service sapmsPRD to work?

Yes you can keep same instance no. but server name is different.

> 3) The hosts in this case have to be different. In this case, how would the logon groups config on the saplogon re-reoute to the right ip ? . How will the saplogon.ini be affected ?

>

> 4) What will need to be done if we need the switch over to be automatic and not manual. That is primary goes down and DR standy senses this and comes up ? . Is this supported in the MSSQL2005 via mirroring and what config in SAP is required to make this work ?

>

> Appreaciate any help on this and if you could guide me to some documents specifically related to MSSQL db

>

SAP Note 965908

Regards,

Nikunj Thaker.

[Former Member]

Nikunj,

The DB team wants to try a different approach. The datafiles and log files of sap system PRD (on host1) are on SAN. The infrastructure team has set up SAN replication between primary site SAN and secondary.site SAN In the case of a DR situation, DB team says they will attach the secondary site SAN LUNS to the DR system (host2) which already has SAP installed. Below are they steps that were done

These are steps covered till now

1) A system refresh of system PRD (host 1) to PRD on (host2) using backup/restore of the PRD database has been performed and then we ran the migration tool of SAPINST (on host 2)

2) DB team has setup SAN replication to secondary SAN at DR site. They are managing it with a SAN replication software.

3) They plan to test the DR by doing the following

a) Pause replication between the 2 SANs

b) Attach the secondary SAN to host 2

c) Map the driver letters for datafiles to be the same as entered during installation of SAP on host2 via SAPinst

4) Start SAP

Will this work ? Will the master db, msdb, model and tempdb of MSSQL server also need to be restored Any ideas on this

regards, Vikram