Are SAP applics. dependant on both server name and IP address?

[MPGraziano]

I know that the server name CANNOT be changed on the 'fly' for the SID for the application to work, however what about the IP address? is it also directly connected to the SAP apllications?

maria

[Former Member · Accepted solution]

Yes Maria

changing the ip address should not be any major issue

But keep following things in mind:

You need to check your RFC connections in SM59 and your hosts file.

If you have set up any external ftp connections to your system, you also need to check if they use IP address or hostname.

If the SAProuter runs on the server you are changing the IP address, you must create a customer message for SAP and ask them to change the IP at their site. The IP address of a SAProuter must be from an official range. You must also update your SAProuter data and change the IP on SAPNet (system-data).

In saprouttab you need to adjust the IP as well

Rohit

[MPGraziano · Accepted solution]

verry verry good.

These things I know and had ommitted to include in my plans

Thank You Rohit!

So if I have a server at the DR site that was inititally installed using same install as the server downstairs here in production. And for me to do maint., I have operations change the server name so that I can keep the server on and on the network. The IP address should not matter eh?

For support and maintanence purpose it does not matter to me if the RFC,s etc, are wrong. I know to change these when we need to kick the server at the DR site into action

maria

[Former Member · Accepted solution]

yes it should not matter

Rohit

[Former Member · Accepted solution]

Hi Maria,

also change host name is possible, but only if your host is not a Production System.

For more information give a look to the following note:

Note 8307 - Changing host name on R/3 host: What do you do?

If you need to change only the IP address, keep in mind to adapt your name resolution resources (DNS and hosts file).

Regards,

Federico Biavati

[MPGraziano · Accepted solution]

Fredrico,

This note relates to R/3 and is dated as 08-05-2006, would this still be relevent to ECC 6.0 on Win 2003 SQL 2005?

The reason we would need to change the server name would be during a site failure/disaster of our main computer room.

Then we would use the computer at the DR site. This computer would have previously been built as an exact replica of the production server including the server name, but as you know we cannot use the 2 same server names on the network so AFTER building the server we would change the name and so we can keep it on the network for the BASIS team to maintain (patches, os patches etc..),

So really this server was installed with the server name of production server, when a disaster (hopefully never) we would shut down (if not already gone) the production server, switch the name of the dr site server to that of the production server.

Maria

[Former Member · Accepted solution]

Hi,

For your need, a better way is to create a DNS alias for your production system and to use only this alis for extenal access (saplogon sapgui, RFC destinations, etc...).

In cas of disaster, you will only change the IP address of the alias to point to the backup server.

Regards,

Olivier

[MPGraziano · Accepted solution]

How does the DNS alias work? and if the computer name is still the same will this not still cause issues?

maria

[MPGraziano · Accepted solution]

Olivier,

I am not using any web application.

We use the GUI to log into SAP (version ECC 6.0 on Win 2003 SP 2, SQL 2005 SP 2).

With creating an alias for DNS, for the server at the DR site, will the application etc.. on that server still run?

I just want to understand how this works? will I need to make changes in SAP (RFCs, sapgui, etc..?) how willl the profile within SAP work? as well printing , transports ?

To clarify why we want to server name change , is so that the OS Patches can be applied during the same time that the OS patches are applied to the production server. I guess IF SAP does NOT come up it is ok, because when the server is required during a disaster (site failure or complete server failer at the production site) we should be able to rename the server back to it's original name (which is the same as the production server) and start up SAP.

But, I would definitely like more information on how the DNS alias works especially with SAP and during disaster.

Maria

[Former Member · Accepted solution]

Hi Maria,

I tested that note only on my architecture (Linux/Oracle) but itu2019s talking also about Windows systems so I donu2019t see why it shouldnu2019t work.

In my experience, the disaster recovery system is installed with different server name and different IP address.

In case of problem, Iu2019ll change my DNS configuration (the Production IP will be pointing to the DR Server) in order to allow my users to access to the DR server without changing SAPGui configuration.

Regards,

Federico Biavati

[MPGraziano · Accepted solution]

Thanks Fredrico,

So your DR server is set up as a completly different servername, and IP address, same SID, then once you need to switch during a failure at your computer centre you would have to do the configurations in the note in order to have the server at the DR site be used? what about the data, do you have a SAN that you can switch to the server at the DR site?

maria

[Former Member · Accepted solution]

Hi Maria,

> So your DR server is set up as a completly different servername, and IP address, same SID,

Yes, exactly

> then once you need to switch during a failure at your computer centre you would have to do the configurations in the note in order to have the server at the DR site be used?

No, the only (and it's a very simple) thing that I have to do is to substitute, in my DNS server, the IP of my Production server name with the IP of my DR server.

In this way everyone will be able to work on the DR server in a transparent way.

I used the note that I forwarded you not for DR reasons, but just because I needed to change the server name and IP of one of my R3 system.

> what about the data, do you have a SAN that you can switch to the server at the DR site?

My Main site and my Disaster Recovery site are 50 km far from each other.

I'm using two different SAN e I'm applying all the DB logs in an asynchronous way.

Let me know if you need more details.

Thanks,

Federico

[MPGraziano · Accepted solution]

Thank You Fredricko

Is'nt your server at the DR site on a differnet IP address (network)

ie. prodn would be 114.155.2.25 and DR would be 114.155.18.32

by switching the IP address of production server to that of the DR server, how quickly will the switch happen? do you have to restart?

BTW, don't your clients log in via GUI, in there the servers are described thru server name etc.. not IP addresses

We would probably not need to apply trans. logs, as we would just unpresent prdn SAN and present it to DR server

[Former Member · Accepted solution]

Hi Maria,

Sorry for the delay,

> Is'nt your server at the DR site on a differnet IP address (network)

Yes, they are in two different locations, and they are using two different subnet.

> by switching the IP address of production server to that of the DR server, how quickly will the switch happen?

Switching the IP address in you DNS is immediate, but you have to force your client in order to read the new information.

The simplest thing to do is as the users to reboot their clients.

> BTW, don't your clients log in via GUI, in there the servers are described thru server name etc.. not IP addresses

Yes exactly, but your clients may keep the u201Cold IP informationu201D for some time, and this is the reason why you have to force them to read flush out the old DNS information (a reboot is the easier thing).

Regards,

Federico Biavati

[MPGraziano · Accepted solution]

I want to thank everyone for their contribution to these questions. They helped me in putting together the following disaster recovery plan for my production servers.

1. Server at DR site about 5kms from computing centre.

2. Base OS installed with hostname different to that of production in the computing centre

3. SIMS installed (to monitor hardware/software)

4. Server setup to do automatic windows updates

To similutate the disaster and implement the server at the DR site the following steps were simulated

1. SAP shutdow on server in computing centre (production) and server turned off

2. Restere C:\ drive from backup tapes to server at DR site (now becomes same server name as that in computing centre (production server)

3. Present CA (SAN) (database, SAP executables etc..) to server at DR site

4. reassigne drive letter for database, SAP executels etc..(because they came up with a drive letter when the CA was presented)

5. Change IP address to server at DR site

6. Start SAP and services

Logged in to verify SAP , sucessfull test!

Maria

[Former Member · Accepted solution]

Thats gr88

Rohit

[Former Member]

Change in IP address means you are changing the BOX also, Port also need to be opened from this sap box to other application box and vice versa.

[MPGraziano]

Yes we are changing the box, but, the non sap application still will be communicating with host name.

Obviously the RFCs will require adjusting as well.

Is this what you were referring to?

Maria

[Former Member]

I mean wherever the IP addresses are mentioned in the external system means which are incoming to the sap system there you need to adjust.No issues with hostname.

[MPGraziano]

Thanks To all of

[JPReyes]

Going back to the Original question.. I can see that nobody suggested you to read SAP Note 403708 - Changing an IP address

Regards

Juan

[Former Member]

Hi,

There should not be any effect as such.

Please make sure that you are changing the IP in rest of the sevrers also so that your applications communication in between the different servers should not be affected.

With Regards,

Saurabh

Edited by: Saurabh.Arora on May 14, 2009 11:15 AM

Edited by: Saurabh.Arora on May 14, 2009 11:16 AM