Building a DR system from DB restore

[Former Member]

Hi Experts,

We currently have a DR system to our production system. Currently this DR system is on a separate network Sub-Domain, and has same SID as the production system. The data base of this DR system has been restored using the SAN replication of the production system.

Now the client has expressed to move this DR in the same Subnet( or same Sub-Domain) as of Production system. I understand that no two systems with Same SID can co exist in the same Subnet . (Please correct me if I am wrong.)

Hence we have 2 alternatives

1. Bring the DR system to Production subnet and somehow change the SID of the DR system . But we are not sure how we can do it

2. Use the SAN replication of Production system and build the new system having a different SID.

Please note that we can do a normal system copy,to create a new system.But that approach requires a downtime of the Source system also ( which is our Production system) .And client do not want to use that approach.

Has anybody ever done a similar exercise . If yes can you please share your expertise .The subject SAP system is SAP-PI 7.0.

Thanks

Bipin Joshi

[Former Member]

Thanks

[ken_halvorsen2]

Hi Bipin

The thing to consider is that your DR system (with the same <sid> as Production) will be in a standby mode, correct. You shouldn't have any problems unless you start it up, which in theory would only be if your Production system is down.

Ken

[Former Member]

usually, DR systems will be build for testing your backups and not for the copy of exisiting systems. You may want to look for homogeneous system copy if you want to build the system as a copy of exisiting system on the same network.

[Former Member]

Hi Manoj,

But If we follow the approach of Homegeneous system copy ,then we might have to keep our Source system down for about few hours . We do not want to do that and want to build this system without impacting the source system.

[Former Member]

If you have to use a DR solution to make alternative avalible immidetaly you have to use SQL replication ( log shipping?) Pls refer to that Sienario.

If Main production system goes down due to DR situation, you can use system copy procedure and restoring latest logfiles avalible.

Regarding your doubt of having same SID systems in same subnet and domain, I don't this it is an issue as long as Server name ( Windows Server name itself) is different.

Following method will should work for you:

1. You will have a Windows System with name Say "DRServer" with say IP 10.1.1.1 and assuming original Prod Server name is "Server" with IP 10.11.11.11

2. When Original Server fails completely, You have to rename DR server name to "Server" and change IP Address to 10.1.1.1

An Windows Specialist will do it with no problem. ( They have to perform tasks like removing original from Main Domain etc and re adding it).

3. You will maintain your DR server with all kernel, windows and SQL Patches when ever you do on Main Prod System.

4. After Step 2, Restore SQL backups from Prod and Transaction logs and you should be ready to go in couple of hours.

With this method, you will not have any issues with RFC connections and any external connections you may have.

Krishna

[markus_doehr2]

> But If we follow the approach of Homegeneous system copy ,then we might have to keep our Source system down for about few hours . We do not want to do that and want to build this system without impacting the source system.

Why that? You can easily use a backup of the source system and use that build up a new system - completely independent from the running source system.

Markus

[Former Member]

Hi Krishna,

Are you sure that 2 SAP servers with same SID can coexist in the same domain. Can both of them can be brought up together , or we will have to shutdown one of them to bring the other one up? Is there any restriction to it.

Although we will not run both of them normally, but sometime it might be needed as we would be working on upgrade or bug fix on one of them while the other one would be up and running.And Of course both these servers will be running on Servers with differnt 'ServerName' and different IP addresses.

Regards

Bipin Joshi

[Former Member]

Hi ,

I think I will have to take my following comment back.

"Regarding your doubt of having same SID systems in same subnet and domain, I don't this it is an issue as long as Server name ( Windows Server name itself) is different. "

Thinking a bit deeper about it, we can restore system from production to DR one, bbut it will work only in DR situation.

Your Sienario will not even work if you put the system in different part of the world independent of network as you will have touble with activating licence of the system with same SID unless you cheat registration procedure saying that duplicate production system is add on application server(or part of cluster/DR)Check legality of this with your SAP account manager.*

So, for bug fixing Preproduction tasks ( ie additioanl QA) you have to have different SID, which can be used in DR situation with same name as I mentioned in steps.

[Former Member]

HI Krishna,

BTW , SAP has confirmed that we can maintain 2 system with same SID in same network domain . However only one can be used as production.

Anyways thanks all for your help

Regards

Bipin