7.20_EXT kernel in a 3-tier environment

[Former Member]

We recently opened a problem report about our development system not restarting. The problem was parameter DIR_LIBRARY_RMT not being set.  In the course of asking "extra" questions, I became concerned about our production environment since it's running 3 tier.

I"m looking for as much detail as I can find on a 3 tier environment running the 7.20_EXT kernel. Can anyone tell me what the parameter DIR_LIBRARY_RMT does exactly? I've been informed a remote app server needs to have a value of pointing to the database DIR_EXECUTABLE thru qfilesvr.400. We also use opticonnect over HSL. Will anything special need to be done for this to function with the new kernel?

thanx
Mark

[christian_bartels]

Hi Mark,

DIR_LIBRARY_RMT is needed to find the kernel library on the database server from a remote application server. In earlier releases, the kernel was trying to resolve the symbolic link '/usr/sap/<sid>/SYS/exe/run/DBSLDB4RMT' to find the kernel library, in 7.20 the application server is calling program R3<sid>400/R3INLPGM to get the kernel library SAP<sid>IND returned. So first of all it appears to be important that program R3<sid>400/R3INLPGM exists on the database server and is up-to-date. Additional information about things to check for DIR_LIBRARY_RMT can be found in SAP Note 1634303. I don't see a reason why DIR_LIBRARY_RMT needs to go through /QFileSvr.400, as far as I can see, the directory is resolved locally on the database server (through a remote program call from the application server to the database server through XDA/XDN).

Kind regards,

Christian Bartels.

[Former Member]

Thanks for the response Christian.  Here was an OSS response when I asked about an ECC 6.0 app server running with the 7.20_EXT kernel.

If it´s on the same LPAR, you can set DIR_LIBRARY_RMT to

$(DIR_EXECUTABLE) or

/usr/sap/<SID>/SYS/exe/run as well. If the app

server is remote, the

parameter must point to IFS kernel directory of

the DB server (e.g. using

/sapmnt).

I was thinking this meant a symbolic link to our db server and the dir_executable.  What do you think?

thanx

Mark

[christian_bartels]

Hi Mark,

the story is getting a bit complicated now, but I am trying to explain it as good as I can. For a detailed description of the background, you may want to have a look at SAP Note 1078134. My first reply is still valid: DIR_LIBRARY_REMOTE needs to contain a value for the executable directory that is valid locally on the database server and not including /QFileSvr.400, an NFS mount or a Windows share.

In systems prior to SAP Basis release 7.10, directory /sapmnt/<SID>/exe contained (PASE) executables and symbolic links to programs in the kernel library. /usr/sap/<SID>/SYS/exe/run was a symbolic link, pointing to /sapmnt/<SID>/exe. DIR_EXECUTABLE would typically point to /usr/sap/<SID>/SYS/exe/run, and you could set DIR_LIBRARY_RMT on IBM i application servers to $(DIR_EXECUTABLE) or /usr/sap/<SID>/SYS/exe/run. On Windows application servers, /usr/sap/<SID>/SYS/exe/run was the only valid option, because DIR_EXECUTABLE would return the Windows directories and not work for the database server. This directory setup is still valid when you later upgraded to the downward-compatible 7.20 or 7.20 EXT kernel, unless you convert it as described in SAP Note 1632754.

Beginning with SAP Basis release 7.10, the kernel would reside in directories /sapmnt/<SID>/exe/uc/as400_pase_64 for Unicode systems or /sapmnt/<SID>/exe/nuc/as400_pase_64 for non-Unicode (ASCII) systems. Each time when an instance is started, new and changed executables are copied from these central directories into instance-specific directories /usr/sap/<sid>/<instance>/exe (or: $(DIR_INSTANCE)/exe) and executed from there. Here, you could define DIR_LIBRARY_RMT as $(DIR_CT_RUN), but /usr/sap/<SID>/SYS/exe/run does still exist and can also be used.

DIR_LIBRARY_RMT is checked through program R3<sid>400/R3INLPGM on the database server, and in 7.20 the check is done by looking for a stream file named .ilelibSAP<sid>IND in the directory specified by DIR_LIBRARY_RMT.

So in general a setup DIR_LIBRARY_RMT = /usr/sap/<SID>/SYS/exe/run in the default profile or all instance profiles should work. To be on the safe side, you can logon with <sid>ADM on the database server and verify with WRKLNK that a file named /usr/sap/<SID>/SYS/exe/run/.ilelibSAP<sid>IND exists there and can be accessed. This is basically the message of SAP Note 1634303, only that it is not explained in that much detail there. I will talk to the owner and see if we can update it.

Kind regards,

Christian.