The adaptive design concept is based upon logically mapping dedicated virtual IP and hostnames and dynamic storage layout to specific applications. In an SAP Landscape Virtualization Management context we ideally map network and storage resources to individual SAP and database instances.
An adaptive enabled system must be stored on central storage. To distribute the different parts of an SAP system on central storage, you have the following options:
- NAS (Network Attached Storage)
Can be shared on multiple hosts at the same time.
- SAN (Storage Area Network)
Is attached to only one host at a given point in time.
What needs to be on central storage and what can be shared depends strongly on the operating system and the database. In general, you have the following options for an adaptive setup of your SAP system database:
- Your database software runs together with your database files and is adaptive installed as a whole unit.
- Your database files are adaptive enabled and SAP Landscape Virtualization Management moves your database around. In this case, the software must be installed on all eligible hosts.
By using virtual hostnames for the SAP and database instances, you ensure that the instances can be relocated from one operating system host to another.
Virtual hostnames are based on DNS (Domain Name System) entries resolved to virtual IP addresses (VIP). VIP addresses can be bonded to any network interface on any operating system host within a given landscape. You can perform matching forward and reverse VIP DNS lookups:
- Forward VIP DNS lookup
Enables clients to use a known domain name during a name query and looks up an IP address based on its domain name. For this process, the DNS requires A (address) records. You cannot use CNAME records.
- Reverse VIP DNS lookup
Enables clients to use a known IP address during a name query and looks up a domain name based on its IP address.
Recommendation: In an adaptive enabled landscape, manage OS and DB users and groups in a central identity management system for instance by using LDAP (Lightweight Directory Access Protocol), NIS (Network Information Service), or Active Directory. If you do not use a central identity management system, ensure that OS and DB users and groups are consistently available on the operating system.