Details about DAA/SMD,host agent, sapstartsrv etc.

Hi admins,

as technology consultant I came across a lot of confusion about topics like host agent, DAA, SMD, sapstartsrv and sapcontrol.

For what all this services are used? Which information is delivered from which one? Do I need them? When should I restart which service?

I will clarify all this questions in this blog to avoid future confusions.

All the communication threads are using the sapstreams (Unix: UNIX-Domain-Sockets / Windows: Windows named pipe).

For more information use the sap help.

Host Agent

The host agent includes also other binaries like saposcol and sldreg.

saposcol

binary which is responsible for the delivery of monitoring values (CPU, memory, I/O etc.) from the OS to ABAP and diagnostic agent/solman

saposcol was included in the normal instance kernel before kernel 720. With kernel 720 it is part of the host agent.

sldreg

deliveres values for SLD (active if dev_sldr, dev_sldregs in instance work dir => /usr/sap/<SID>/work)

You need it if you want to send all information of your system to SolMan

to activate it => sldreg -configure slddest.cfg –usekeyfile => creates a config file in global dir

will send data if you are restarting the sapstartsrv of the instance => sapcontrol -nr xx -function RestartService

Note: this will only restart the sapstartsrv not the SAP instance or the system!

sapstartsrv

Note: every instance has its own service => this means e.g. DAA, central services (SCS), host agent have its own sapstartsrv process

Over this service and its ports the execution of OS commands is possible. The sapcontrol binary controls this service and can restart the system.

This means SAP MC (Management Console) uses this port for communication and commands.

The service should be restarted if you change anything on your system, e.g. kernel, IP, hostname

DAA / SMD

In newer systems there is no difference between SMD and DAA. The diagnostic agent (DAA) is the newer description but includes the SMD which is more the instance description and DAA the SID. They renamed SMD to DAA, it is still nearly the same and you will find both names in the documentations or parameters.

Details: based on java instance

It is a central component of the solution manager. You should install it on every system which you want to connect to the SolMan. It provides necessary information for SLD/LMDB.

sapcontrol

The sapcontrol binary uses the sapstartsrv to start/stop services, read out log and trace files, show details and status of processes

Details:

You can only restart a service, instance or a complete system. Now some of you may be confused about this. Is the instance not the same as system?

No the instance is e.g. only the DIA instance but not the ASCS and the DB. When you stop the system, than all process which are registered in <GlobalDir>/sapcontrol are restarted!

You can display this also with a command: sapcontrol -nr xx -function GetSystemInstanceList

some useful functions:

GetStartProfile

GetTraceFile

GetAlerts

GetEnvironment

GetVersionInfo

GetQueueStatistic

GetProcessList

GetInstanceProperties

GetSystemInstanceList

ABAPReadSyslog

ABAPGetWPTable

J2EEGetProcessList

J2EEGetThreadList

J2EEGetSessionList

ICMGetCacheEntries

EnqGetStatistic

EnqGetLockTable

CheckHostAgent

I hope I could clarify the meaning and usage of every service/binary.

If you have any further questions, don’t hestate to comment the blog or contact me or one of my colleagues at Q-Partners ( info_at_qpcm_dot_de )

Best Regards,

Jens Gleichmann

Technology Consultant at Q-Partners (www.qpcm.eu)