SAP recovery & other doubts.

[Former Member]

Hi All,

1 ) We have a SAP Ides system installed on Red Hat Linux 5.3 & db2 in which the OS crashed & the OS administration team Re installed Linux by formatting / ( root ) & /boot directory but did not touch other directories like /usr , /sapmnt , /opt etc . Now is it possible to some how bring up SAP by using old files ( we have taking file system backup of old / & /boot directory ) . I tried to start SAP but found out that SIDADM user is not available since the OS was re installled ?

2) The network team wants to change the IP Adress of some SAP systems . Now what is the impact of changing the ip adress , gateway , subnet mask of already installed SAP system ? What are the pre cautions to be taken before going for these changes ?

Thanks

Sunil Kumar

[nirmal_konchada · Accepted solution]

>

> Hi All,
> 
> 1 )  We have a SAP Ides system installed on Red Hat Linux 5.3 & db2 in which the OS crashed & the OS administration team Re installed Linux by formatting   / ( root )   & /boot directory but did not touch other directories  like /usr , /sapmnt , /opt etc .  Now is it possible to some how bring up SAP by using old files   ( we have taking file system backup of old / & /boot directory ) .  I tried to start SAP but found out that SIDADM user is not available since the OS was re installled ?  

You can again create the uers using sapinst. But make sure that you use the same GID and UID for them. Even the user environment needs to e setup.

>

>

> 2)  The network team wants to change the IP Adress of some SAP systems .  Now what is the impact of changing the ip adress , gateway , subnet mask  of already installed SAP system  ? What are the pre cautions to be taken before going for these changes ?
> 

You can use this note for IP change : Note 403708 - Changing an IP address

Regards,

Nirmal.K

[Former Member · Accepted solution]

Hi Nirmal ,

Wont running of sapinst re install SAP again . Before running sap inst do I need to move the existing files ( /usr, /sapmnt , /db2 , /opt etc ) to other location like external disk & move the contents back to the new installed SAP sytem ? what are the sequence of steps to achieve this ?

Thanks

Sunil Kumar

[nirmal_konchada · Accepted solution]

Hi,

Using sapinst for creating users doesnt install the SAP system

You need to use the create users and groups option under additional tasks of sapinst.

NOTE : Dont install a fresh SAP system.

Regards,

Nirmal.K

[Former Member · Accepted solution]

I know this won't help you much at the moment, but consider for the future:

Usually the OS admins should be able to recover the OS to the state it was before the problem (including OS users, /etc/services and everything). There are special tools to do such "bare metal restores". How do they guarantee the same OS patches / RPM's in your case?

And in most cases a complete restore/recovery of the OS is not needed after a "system crash".

To answer your question about the change of an IP address:

- existing firewall rules would have to be changed (saprouter/oss connection)

- if you have RFC connections with IP addresses, you will have to change them.

But if the hostname stays the same, this is basically it.

Cheers Michael