SAP Start Service in HA environments
SAP Start Service or sapstartsrv is a Unix daemon / Windows service assigned to an SAP instance. It controls and monitors the assigned instance. Since sapstartsrv is a vital part of any SAP instance and due its specific feature a proper HA setup needs to handle sapstartsrv correctly and can make use of its features. This paper provides some information which should help HA partners to handle it correctly Download the DocumentPUBLIC
SAP Start Service in HA environments
Date: 2025-01-03
Owner: Server Infrastructure Team
SAP Start Service in HA environments
Date: 2025-01-03
Owner: Server Infrastructure Team
© 2025 SAP SE or an SAP affiliate company. All rights reserved. See Legal Notice on www.sap.com/legal-notice for use terms, disclaimers, disclosures, or restrictions related to this material. 2 / 6
Table of contents
Introduction ................................................................................................................................................................. 3
Sapstartsrv Startup and Lifecycle ..................................................................................................................... 3
Instance Start/Stop .................................................................................................................................................. 4
Instance Monitoring ................................................................................................................................................. 4
Webservice Authentication .................................................................................................................................. 5
Sapcontrol Command Line Tool ........................................................................................................................ 5
Error Handling and Cleanup................................................................................................................................. 5
SAP HA Shared Library Interface ....................................................................................................................... 6
Documentation .......................................................................................................................................................... 6
Table of contents
Introduction ................................................................................................................................................................. 3
Sapstartsrv Startup and Lifecycle ..................................................................................................................... 3
Instance Start/Stop .................................................................................................................................................. 4
Instance Monitoring ................................................................................................................................................. 4
Webservice Authentication .................................................................................................................................. 5
Sapcontrol Command Line Tool ........................................................................................................................ 5
Error Handling and Cleanup................................................................................................................................. 5
SAP HA Shared Library Interface ....................................................................................................................... 6
Documentation .......................................................................................................................................................... 6
© 2025 SAP SE or an SAP affiliate company. All rights reserved. See Legal Notice on www.sap.com/legal-notice for use terms, disclaimers, disclosures, or restrictions related to this material. 3 / 6
Introduction
Sap Start Service or sapstartsrv is a Unix daemon / Windows service assigned to an SAP instance. It controls
and monitors the assigned instance. Since sapstartsrv is a vital part of any SAP instance and due its specific
feature a proper HA setup needs to handle sapstartsrv correctly and can make use of its features. This paper
provides some information which should help HA partners to handle it correctly.
There is one additional sapstartsrv installed once per hosts offering OS, database and LM related
functionality. The following is not related to this SAP Hostagent sapstartsrv. SAP Hostagent must not be
handled by a HA setup. It is installed on a machine and must not be moved by a HA failover.
Sapstartsrv Startup and Lifecycle
On Windows, sapstartsrv is installed as a Windows service. By default, it is installed with startup type
“Automatic”. It provides a self-registration / unregistration capability via “-r” and “–u” option.
On UNIX sapstartsrv runs as a daemon. This is achieved by installing “sapinit” once on the machine. Each
sapstartsrv gets registered in /usr/sap/services. The self-registration / unregistartion capability is provided via
“-reg” and “–unreg” option.
This way sapstartsrv is designed to get started at OS boot and remains running “forever”. Even if the assigned
SAP instances gets stopped sapstartsrv remains running. However, when applying a kernel patch it will get
updated via sapcpe during instance start. In this case sapstartsrv will restart itself 5 minutes after the update
happened.
In a HA setup sapstartsrv must be moved together with the assigned instance. Furthermore, the HA setup
must ensure that sapstartsrv is only running on the cluster node which actually owns the assigned instance.
Typically, one the following two solutions can be used:
• Sapstartsrv is registered on both/all cluster nodes. In this case the HA solution must ensure it can
and will only be started on one of the nodes. E.g. on Windows the service startup type can be
switched to “Manually” and service startup is controlled by the HA solution. Another option is to
ensure the file system hosting the instance executables is only accessible on one cluster node.
• Sapstartsrv is only registered on the active cluster node. In this case the HA solution must unregister
and register sapstartsrv during a failover.
Sapstartsrv can also be restarted manually via its webservice function “RestartService”, e.g. triggered by an
Administrator via SAP MMC / MC or sapcontrol to activate certain configuration changes. A HA solution must
handle manual and automatic sapstartsrv restarts, e.g. by tolerating short term sapstartsrv unavailable
situations. Long term sapstartsrv failure should be handled by the HA solution. The HA solution may try to
restart a failed sapstartsrv using function “StartService” of the “sapcontrol” command line tool. If sapstartsrv
can be restarted it will pick up the instance processes automatically and continue operating as usual.
By using webservice function “StopService” sapstartsrv can be stopped without stopping the instance. If
sapstartsrv is stopped normally (Windows Service control manager or SIGINT) it will stop the assigned
instance as well.
Introduction
Sap Start Service or sapstartsrv is a Unix daemon / Windows service assigned to an SAP instance. It controls
and monitors the assigned instance. Since sapstartsrv is a vital part of any SAP instance and due its specific
feature a proper HA setup needs to handle sapstartsrv correctly and can make use of its features. This paper
provides some information which should help HA partners to handle it correctly.
There is one additional sapstartsrv installed once per hosts offering OS, database and LM related
functionality. The following is not related to this SAP Hostagent sapstartsrv. SAP Hostagent must not be
handled by a HA setup. It is installed on a machine and must not be moved by a HA failover.
Sapstartsrv Startup and Lifecycle
On Windows, sapstartsrv is installed as a Windows service. By default, it is installed with startup type
“Automatic”. It provides a self-registration / unregistration capability via “-r” and “–u” option.
On UNIX sapstartsrv runs as a daemon. This is achieved by installing “sapinit” once on the machine. Each
sapstartsrv gets registered in /usr/sap/services. The self-registration / unregistartion capability is provided via
“-reg” and “–unreg” option.
This way sapstartsrv is designed to get started at OS boot and remains running “forever”. Even if the assigned
SAP instances gets stopped sapstartsrv remains running. However, when applying a kernel patch it will get
updated via sapcpe during instance start. In this case sapstartsrv will restart itself 5 minutes after the update
happened.
In a HA setup sapstartsrv must be moved together with the assigned instance. Furthermore, the HA setup
must ensure that sapstartsrv is only running on the cluster node which actually owns the assigned instance.
Typically, one the following two solutions can be used:
• Sapstartsrv is registered on both/all cluster nodes. In this case the HA solution must ensure it can
and will only be started on one of the nodes. E.g. on Windows the service startup type can be
switched to “Manually” and service startup is controlled by the HA solution. Another option is to
ensure the file system hosting the instance executables is only accessible on one cluster node.
• Sapstartsrv is only registered on the active cluster node. In this case the HA solution must unregister
and register sapstartsrv during a failover.
Sapstartsrv can also be restarted manually via its webservice function “RestartService”, e.g. triggered by an
Administrator via SAP MMC / MC or sapcontrol to activate certain configuration changes. A HA solution must
handle manual and automatic sapstartsrv restarts, e.g. by tolerating short term sapstartsrv unavailable
situations. Long term sapstartsrv failure should be handled by the HA solution. The HA solution may try to
restart a failed sapstartsrv using function “StartService” of the “sapcontrol” command line tool. If sapstartsrv
can be restarted it will pick up the instance processes automatically and continue operating as usual.
By using webservice function “StopService” sapstartsrv can be stopped without stopping the instance. If
sapstartsrv is stopped normally (Windows Service control manager or SIGINT) it will stop the assigned
instance as well.
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Instance Start/Stop
Instance start/stop is triggered via webservice functions “Start” / “Stop” of sapstartsrv. Traditional SAP
start/stop command line tools have been adapted to use the webservice interface as well (directly or via
“sapcontrol” command line tool). On Windows the deprecated DCOM interface of sapstartsrv still exists but
should not be used anymore.
On UNIX, sapstartsrv does not launch the instance process directly. Instead, “sapstart” is used to actually
start the processes. Anyway, “sapstart” should not be used directly to start the instance (bypassing
sapstartsrv).
The actually started processes are configured in the profile using Start_Program_<NR> profile parameters.
By using Restart_Program_<NR> parameter instead, a process which died unexpectedly gets restarted
automatically. This may e.g. be used to restart the message server in case of failure to avoid a complete SCS
instance failover if possible or to restart the enqueue replication server of the ERS instances automatically
after a successful lock table transfer.
Instance Monitoring
The major webservice function to monitor the instance status is “GetProcessList”. It returns a list of all
processes started via the profile. Each process has a status color:
• Gray: Stopped
• Yellow: Running with problems or a synchronous temporary process like “sapcpe” executed during
startup
• Green: Running
• Red: Could not be started
For most critical process a status monitoring beyond just “process is running” is performed:
• disp+work: Verify instance is connected to message server, verify dialog queue info can be read from
shared memory, verify progress in dialog queue processing. In case of double stack jstart/jcontrol
status is integrated
• jstart/jcontrol: Verify status information from AS Java startup framework
• enq_server: Verify enqueue statistic can be retrieved from enqueue server
• msg_server: Verify message server client list can be retrieved from message server
An instance is considered as fully available if all processes have a green status. The overall instance status is
reported by sapstartsrv every 60 sec in available.log in DIR_HOME of the assigned instance. During the first
restart after a kernel switch the status of disp+work, jstart, jcontrol may remain yellow for some minutes
although the instance is fully operational until sapstartsrv gets (automatically) restarted. This is caused by
using shared memory for monitoring which may cause an old sapstartsrv to fail accessing the shared memory
created by a new version of disp+work, jstart, jcontrol. A HA solution needs to handle temporary “yellow”
status of processes.
“EnqGetLockTable” and “EnqGetStatistic” can be used to monitor the enqueue server in more detail.
Especially “EnqGetStatistic” / “EnqGetStatistic2” provides information about the replication state which may
be used to avoid triggering failovers in case of missing or failed replication.
“J2EEGetProcessList” provides additional status information for AS Java.
Instance Start/Stop
Instance start/stop is triggered via webservice functions “Start” / “Stop” of sapstartsrv. Traditional SAP
start/stop command line tools have been adapted to use the webservice interface as well (directly or via
“sapcontrol” command line tool). On Windows the deprecated DCOM interface of sapstartsrv still exists but
should not be used anymore.
On UNIX, sapstartsrv does not launch the instance process directly. Instead, “sapstart” is used to actually
start the processes. Anyway, “sapstart” should not be used directly to start the instance (bypassing
sapstartsrv).
The actually started processes are configured in the profile using Start_Program_<NR> profile parameters.
By using Restart_Program_<NR> parameter instead, a process which died unexpectedly gets restarted
automatically. This may e.g. be used to restart the message server in case of failure to avoid a complete SCS
instance failover if possible or to restart the enqueue replication server of the ERS instances automatically
after a successful lock table transfer.
Instance Monitoring
The major webservice function to monitor the instance status is “GetProcessList”. It returns a list of all
processes started via the profile. Each process has a status color:
• Gray: Stopped
• Yellow: Running with problems or a synchronous temporary process like “sapcpe” executed during
startup
• Green: Running
• Red: Could not be started
For most critical process a status monitoring beyond just “process is running” is performed:
• disp+work: Verify instance is connected to message server, verify dialog queue info can be read from
shared memory, verify progress in dialog queue processing. In case of double stack jstart/jcontrol
status is integrated
• jstart/jcontrol: Verify status information from AS Java startup framework
• enq_server: Verify enqueue statistic can be retrieved from enqueue server
• msg_server: Verify message server client list can be retrieved from message server
An instance is considered as fully available if all processes have a green status. The overall instance status is
reported by sapstartsrv every 60 sec in available.log in DIR_HOME of the assigned instance. During the first
restart after a kernel switch the status of disp+work, jstart, jcontrol may remain yellow for some minutes
although the instance is fully operational until sapstartsrv gets (automatically) restarted. This is caused by
using shared memory for monitoring which may cause an old sapstartsrv to fail accessing the shared memory
created by a new version of disp+work, jstart, jcontrol. A HA solution needs to handle temporary “yellow”
status of processes.
“EnqGetLockTable” and “EnqGetStatistic” can be used to monitor the enqueue server in more detail.
Especially “EnqGetStatistic” / “EnqGetStatistic2” provides information about the replication state which may
be used to avoid triggering failovers in case of missing or failed replication.
“J2EEGetProcessList” provides additional status information for AS Java.
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“GetAlertTree” and “GetAlerts” provide general CCMS status information (similar to rz20 transaction)
“GetSystemInstanceList” provides information on all instances of the system (updated asynchronously every
60 sec by each sapstartsrv in the system).
Webservice Authentication
The webservice interface of sapstartsrv requires client authentication for executing critical functions like
“Start” or “Stop”. By default, almost all functions are protected. However, SAP customers are free change this
setting according to their security requirements. A HA product using the webservice interface must be able to
provide proper authentication. By default, http basic authentication with OS <sid>adm user and password
can be used. For local connections a so called “trusted connect” can be used via the “sapcontrol” command
line tool (Option: Windows: “-prot PIPE”, UNIX: “-prot NI_HTTP” (default)). This way when executed as
<sid>adm all functions of the webservice interface can be executed without explicitly providing OS user and
password.
For more details and advanced security features please refer to SAP note 927637 and 1439348.
Sapcontrol Command Line Tool
The HA product can access the webservice interface of sapstartsrv by using the “sapcontrol” command line
tool or by implementing a webservice client on its own. By using the “sapcontrol” tool a trusted connect can
be used (see above), however the output of sapcontrol needs to be analyzed by the HA product in this case.
Sapcontrol provides some exit codes to detect success or failure of an operation:
0 Last webmethod call successful
1 Last webmethod call failed, invalid parameter
2 StartWait, StopWait, WaitforStarted, WaitforStopped, RestartServiceWait timed out
3 GetProcessList succeeded, all processes running correctly
4 GetProcessList succeeded, all processes stopped
Furthermore option “-format script” can be used to generate an easy to parse output format.
Error Handling and Cleanup
Since sapstartsrv is a mandatory component, for normal instance stop additional steps are necessary to stop
an instance in case of permanent sapstartsrv failure. In general SAP processes can be stopped using SIGINT
signal. A soft shutdown can be triggered via SIGQUIT. Finally, processes can be killed by using
“TerminateProcess” / SIGKILL. On Windows sapstartsrv creates a JobObject named SAP<SID>_<NR> which
hosts all processes of the assigned instance (including sapstartsrv itself). This can be used to find any
dangling processes which need to be stopped for cleanup. On UNIX “kill.sap” and “shutdown.sap” are
generated in DIR_HOME during instance startup. They can be used to send a SIGINT to “sapstart” or the child
processes of “sapstart”.
During normal instance start/stop shared memory is cleaned up by the instance processes. In case of
problems this may not always be performed correctly. On Windows SAP shared memory is automatically
“GetAlertTree” and “GetAlerts” provide general CCMS status information (similar to rz20 transaction)
“GetSystemInstanceList” provides information on all instances of the system (updated asynchronously every
60 sec by each sapstartsrv in the system).
Webservice Authentication
The webservice interface of sapstartsrv requires client authentication for executing critical functions like
“Start” or “Stop”. By default, almost all functions are protected. However, SAP customers are free change this
setting according to their security requirements. A HA product using the webservice interface must be able to
provide proper authentication. By default, http basic authentication with OS <sid>adm user and password
can be used. For local connections a so called “trusted connect” can be used via the “sapcontrol” command
line tool (Option: Windows: “-prot PIPE”, UNIX: “-prot NI_HTTP” (default)). This way when executed as
<sid>adm all functions of the webservice interface can be executed without explicitly providing OS user and
password.
For more details and advanced security features please refer to SAP note 927637 and 1439348.
Sapcontrol Command Line Tool
The HA product can access the webservice interface of sapstartsrv by using the “sapcontrol” command line
tool or by implementing a webservice client on its own. By using the “sapcontrol” tool a trusted connect can
be used (see above), however the output of sapcontrol needs to be analyzed by the HA product in this case.
Sapcontrol provides some exit codes to detect success or failure of an operation:
0 Last webmethod call successful
1 Last webmethod call failed, invalid parameter
2 StartWait, StopWait, WaitforStarted, WaitforStopped, RestartServiceWait timed out
3 GetProcessList succeeded, all processes running correctly
4 GetProcessList succeeded, all processes stopped
Furthermore option “-format script” can be used to generate an easy to parse output format.
Error Handling and Cleanup
Since sapstartsrv is a mandatory component, for normal instance stop additional steps are necessary to stop
an instance in case of permanent sapstartsrv failure. In general SAP processes can be stopped using SIGINT
signal. A soft shutdown can be triggered via SIGQUIT. Finally, processes can be killed by using
“TerminateProcess” / SIGKILL. On Windows sapstartsrv creates a JobObject named SAP<SID>_<NR> which
hosts all processes of the assigned instance (including sapstartsrv itself). This can be used to find any
dangling processes which need to be stopped for cleanup. On UNIX “kill.sap” and “shutdown.sap” are
generated in DIR_HOME during instance startup. They can be used to send a SIGINT to “sapstart” or the child
processes of “sapstart”.
During normal instance start/stop shared memory is cleaned up by the instance processes. In case of
problems this may not always be performed correctly. On Windows SAP shared memory is automatically