SAP Basis Tech Supports

Symptom
(1) When ativating a virtual hostname via Hostagent/sapacosprep on a Linux box, the following warning message will be returned: “LNX-3010: Could not refresh ARP cache”. The sapacosprep.log file includes the following error: “socket: Address family not supported by protocol”. In the /var/log/messages file you may find an error like: “modprobe: FATAL: Could not load /lib/modules/<your kernel version>/modules.dep”
(2) If deactivating a virtual hostname on one interface on Linux, all subsequent aliases on the same interface are also deleted
(3)If delete Mount Point options is used, Mount Points are deleted on unix, even if there is an overmounted filesystem still present
(4) Manually added NFS shares with a tailing slash ‘/’ can not be unmounted under linux using the sapacosprep
(5)On Windows, you can not access a fileshare via the virtual hostname. This results in “Permission Denied” Errors, e.g. on several Instance Agent Operations, which require the access to the profile.
(6) On Windows, the reverse lookup (e.g. via ping -a <IP-Address>)of virtual hostnames might return the physical instead of the virtual hostname if DNS is used. Therefore the ACC will not be able to determine the correct service status.
(7)the sapacosprep deactivates interfaces, even if multiple addresses are activated on on interface (or interface alias)
Other terms
saphostcontrol saphostexec adaptive computing controller ACC linux
Reason and Prerequisites
(1) The implementation of the ARP cache refresh functionality depends on the Linux packet socket interface, which is not available.
(2) This happens on Linux with Kernel >= 2.6.15
(7) this can happen, if you are using distribution configuration tools to activate the ip-addresses on one interface, e.g. via YAST on SuSE
Solution
(1) It must be ensured that the af_inet kernel module, which implements the packet interface, is loaded either dynamically with the help of the modprobe mechanism (default and prefered) or by compiling it into the kernel. The modprobe mechanism depends on a modules.dep file located in the directory /lib/modules/<kernel version>. Ensure that this file exists and that it fits to your running kernel version.
(2)You can manually set/add the parameter net.ipv4.conf.<interface-number or “all”>.promote_secondaries to the value 1 via the sysctl command, or install the SAP Hostagent SP xx, which will set this parameter temporary, while deactivating the virtual hostname.
(3) Install the SAP Hostagent 711 SP 19
(4) Install the SAP Hostagent 711 SP 19
(5) This is a security feature of Microsoft Windows (http://support.microsoft.com/kb/896861) You can either apply the described method 1 or 2. If neither of these methods is used, the sapacosprep will set the DisableLoopbackCheck automatically ( 711 SP 19 required). If you choose to add the virtual hostname to the “BackConnectionHostNames” (Method 2), than you have to manually remove the entries as soon as the virtual hostname is deactivated.
If you want to avoid modification of the DisableLoopbackCheck, you have to set the Environment Variable “sap_disable_loopback_check” to “false”. However, you may run into functional problems described under Syntoms(5).
(6) You can add the IP/hostnames to the c:\Windows\system32\drivers\etc\hosts. Since SAP Hostagent 711 SP 19 this can be done automatically, if the environment of local system account contains the following variable “sap_nt_ip_workaround” with the value “hosts”.
(7) Do not use any distribution tools to activate virtual ip-addresses on a AC-enabled host. Deactivate all virtual ip-addresses used by AC-enabled services before executing any Prepare/Unprepare Operations.
Since SAP Hostagent 711 SP 19 the sapaocsprep won’t deactivate the interface but will report an error.