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Difference between ASCS and CI

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Former Member

on ‎2011 Dec 06 3:59 AM

0 Likes
36,510

Hi Experts,

I am a bit confused with the difference between the terminologies ASCS and CI. With the introduction of ASCS the Message and Enqueue services are separated from CI then why does CI terminology still exists in the installation guide or for that reason why do we still have to install CI in HA set up?

What services will be there in CI with the existence of ASCS? Will the CI still hold Message server and Enqueue server and will be a replica of ASCS?

The simplest HA setup what I understand is this-

Node A- ASCS + CI + DB (With DB and ASCS as SPOFs and clustered)

Node B - DI

So with this when Node A fails ASCS and DB gets moved to Node B and DI on Node B takes the place of CI. But my confusion here is if DI is taking the place of CI then CI and and DI becomes same in the whole architecture. Is it so?

Regards

Sourabh Majumdar

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former_member182505
Contributor
‎2011 Dec 06 4:25 AM
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Hi

AS ABAP instance of an SAP system containing the enqueue server and the message server (ASCS = ABAP SAP Central Services). There can only be one such instance in the SAP system, and it can be made into a high availability SPOF (single point of failure) instance.

The enqueue replication server (ERS instance) is set up for this.

Alternatively, you can work on an an ABAP system with the classical central instance (containing the enqueue work process - usually the message server is is also running on this system).

What is ASCS/SCS?

With SAP NetWeaver 04 Java, the Message Server and the Enqueue Server are separated from the Central Instance. These two services are grouped within the SAP Central Services Instance (SCS) as services. From NW04s the ABAP Central Services can be also separated from the Central Instance. Each stack, ABAP and Java, has its own Message Service and Enqueue Service. For ABAP systems the Central Services are referred to as ASCS, for Java systems the Central Services are referred to as SCS. The ASCS and the SCS are leveled as SPOF and require a High Availability Setup therefore. If the ASCS is integrated within the ABAP Central Instance (standard in NetWeaver 04) the Central Instance of the ABAP system needs a HA setup also.

The central instance is a concept that is unique to SAP. The central instance is a combination of hardware and software. It contains a physical server (the application server) and numerous software components, including a message server, a database gateway (a pre-established connection between SAP and Oracle--or another database), and various update, enqueue, dialog, and spool facility software. In most generic SAP architectures, there are numerous application servers but only a single central instance. However, in addition to managing the SAP interfaces, the central instance can also serve as an application server

For more detail for HA please CHECK LINK..

http://scn.sap.com/docs/DOC-25454

Thanks

Sadiq

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Former Member
‎2011 Dec 06 4:38 AM
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Hi Sadiq,

You have pasted it directly picking up from standard documentation but what I am looking is the conceptual/logical difference behind the the simultaneous existence of ASCS and CI of SAP.

Can you clearly explain my questions what I asked in my post.

Regards

Sourabh Majumdar

former_member182505
Contributor
‎2011 Dec 06 4:41 AM
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hi,

recently we have installed ASCSCIDB in a server and DI on node2.

with DI we also installed the ERS, on node 2 and its working fine.

when we are swithing for node1 to node2 ERS is taking care of the SOPF.

thanks

sadiq

Former Member
‎2011 Dec 06 4:47 AM
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Okay so here the ERS is a standalone enqueue server but what I am looking for is what is the need of CI when ASCS is present (because the classical concept says that CI contains MS and ENQ and when that is moved to ASCS then what will comprise CI).

Or is it that CI and DI becomes same when ASCS in place? Because MS and ENQ is needed for entire SAP system to remain functional and these are part of ASCS which in any case is clustered and never becoming down.

Regards

Sourabh Majumdar

former_member182505
Contributor
‎2011 Dec 06 5:11 AM
0 Likes

Hi

Here i am pasting my instance Profile details please check it may help you to understant,

more HSP_ASCS01_scsHSP

SAPSYSTEMNAME = HSP

SAPSYSTEM = 01

INSTANCE_NAME = ASCS01

DIR_CT_RUN = $(DIR_EXE_ROOT)/run

DIR_EXECUTABLE = $(DIR_INSTANCE)/exe

SAPLOCALHOST = scsHSP

#----

  1. SAP Message Server parameters are set in the DEFAULT.PFL

#----

ms/standalone = 1

ms/server_port_0 = PROT=HTTP,PORT=81$$

#----

  1. SAP Enqueue Server

#----

enque/table_size = 4096

rdisp/enqname = $(rdisp/myname)

enque/snapshot_pck_ids = 100

ssl/ssl_lib = $(DIR_EXECUTABLE)$(DIR_SEP)$(FT_DLL_PREFIX)sapcrypto$(FT_DLL)

sec/libsapsecu = $(ssl/ssl_lib)

ssf/ssfapi_lib = $(ssl/ssl_lib)

enque/server/replication = true

more HSP_DVEBMGS00_ciHSP

#.******************************************************************************

************************************************

#.*

*

#.* Instance profile HSP_DVEBMGS00_CIHSP

*

#.*

*

#.* Version = 000007

*

#.* Generated by user = BASIS

*

#.* Generated on = 04.09.2011 , 16:55:50

*

#.*

*

#.******************************************************************************

************************************************

#parameter created by: BASIS 04.09.2011 16:55:24

rdisp/gui_auto_logout = 900

#parameter created by: BASIS 30.08.2011 16:35:49

login/multi_login_users = BASIS

#parameter created by: BASIS 30.08.2011 11:59:06

login/disable_multi_gui_login = 1

#parameter created by: BASIS 12.08.2011 17:16:51

abap/buffersize = 1500000

#parameter created by: BASIS 12.08.2011 17:14:48

rsdb/obj/buffersize = 75000

#parameter created by: BASIS 12.08.2011 17:14:20

rsdb/obj/max_objects = 20000

#parameter created by: BASIS 12.08.2011 17:13:37

rsdb/cua/buffersize = 45000

#parameter created by: BASIS 12.08.2011 17:13:19

rsdb/ntab/ftabsize = 120000

#parameter created by: BASIS 12.08.2011 17:12:59

rsdb/ntab/entrycount = 45000

#parameter created by: BASIS 12.08.2011 17:12:42

rsdb/ntab/irbdsize = 8000

#parameter created by: BASIS 12.08.2011 17:12:24

rtbb/buffer_length = 60000

#parameter created by: BASIS 12.08.2011 17:12:08

zcsa/table_buffer_area = 100000000

#parameter created by: BASIS 12.08.2011 17:11:46

zcsa/db_max_buftab = 10000

#parameter created by: BASIS 12.08.2011 17:11:23

zcsa/presentation_buffer_area = 35000000

#parameter created by: BASIS 12.08.2011 17:10:56

sap/bufdir_entries = 10000

#parameter created by: BASIS 12.08.2011 17:10:04

em/initial_size_MB = 9216

#parameter created by: BASIS 12.08.2011 17:09:44

em/global_area_MB = 255

#parameter created by: BASIS 12.08.2011 17:09:26

  1. *** PERMANENT 701 CHANGE ***"

#ztta/short_area = 4000000

#parameter created by: BASIS 12.08.2011 17:08:55

rdisp/max_arq = 2000

#parameter created by: BASIS 12.08.2011 17:08:30

rdisp/wp_ca_blk_no = 2000

#parameter created by: BASIS 12.08.2011 17:07:29

rdisp/appc_ca_blk_no = 2000

#parameter created by: BASIS 12.08.2011 17:07:09

gw/max_conn = 2000

#parameter created by: BASIS 12.08.2011 17:06:52

rdisp/tm_max_no = 2000

#parameter created by: BASIS 12.08.2011 17:06:35

rdisp/max_comm_entries = 2000

#parameter created by: BASIS 12.08.2011 17:06:07

gw/max_overflow_size = 25000000

#parameter created by: BASIS 12.08.2011 17:05:30

gw/max_sys = 2000

#parameter created by: BASIS 12.08.2011 17:04:11

enque/table_size = 10000

SAPSYSTEMNAME = HSP

SAPSYSTEM = 00

INSTANCE_NAME = DVEBMGS00

DIR_CT_RUN = $(DIR_EXE_ROOT)/run

DIR_EXECUTABLE = $(DIR_INSTANCE)/exe

SAPLOCALHOST = ciHSP

ssl/ssl_lib = $(DIR_EXECUTABLE)$(DIR_SEP)$(FT_DLL_PREFIX)sapcrypto$(FT_DLL)

sec/libsapsecu = $(ssl/ssl_lib)

ssf/ssfapi_lib = $(ssl/ssl_lib)

login/accept_sso2_ticket = 1

login/create_sso2_ticket = 2

exe/saposcol = $(DIR_CT_RUN)/saposcol

#old_value: 10

changed: BASIS 12.08.2011 17:01:14

rdisp/wp_no_dia = 20

#old_value: 3

changed: BASIS 12.08.2011 17:01:14

rdisp/wp_no_btc = 6

exe/icmbnd = $(DIR_CT_RUN)/icmbnd

icm/server_port_0 = PROT=HTTP,PORT=80$$

#old_value: 1

changed: BASIS 02.09.2011 13:10:01

rdisp/wp_no_vb = 2

#old_value: 1

changed: BASIS 02.09.2011 13:10:01

rdisp/wp_no_vb2 = 2

#parameter created by: BASIS 12.08.2011 17:01:27

login/no_automatic_user_sapstar = 0

#old_value: 1

changed: BASIS 02.09.2011 13:10:01

rdisp/wp_no_spo = 2

#----

#Values proposed by SAP for shared memory pool sizes

#----

#parameter created by: BASIS 12.08.2011 17:18:02

  1. *** PERMANENT 701 CHANGE ***"

#ipc/shm_psize_10 = 124000000

ipc/shm_psize_10 = 728000000

#parameter created by: BASIS 12.08.2011 17:18:02

ipc/shm_psize_14 = 0

#parameter created by: BASIS 12.08.2011 17:18:02

ipc/shm_psize_18 = 0

#parameter created by: BASIS 12.08.2011 17:18:02

ipc/shm_psize_19 = 0

#parameter created by: BASIS 12.08.2011 17:18:02

ipc/shm_psize_30 = 0

#parameter created by: BASIS 12.08.2011 17:18:02

ipc/shm_psize_40 = 266000000

#parameter created by: BASIS 12.08.2011 17:18:02

ipc/shm_psize_41 = 0

more HSP_ERS02_ersHSP

SAPSYSTEMNAME = HSP

SAPSYSTEM = 02

INSTANCE_NAME = ERS02

DIR_CT_RUN = /usr/sap/HSP/SYS/exe/run

#DIR_CT_RUN = $(DIR_EXE_ROOT)/run

DIR_EXECUTABLE = $(DIR_INSTANCE)/exe

SAPLOCALHOST = ersHSP

#----

  1. Settings for enqueue monitoring tools (enqt, ensmon)

#----

enque/process_location = REMOTESA

rdisp/enqname = $(rdisp/myname)

#----

  1. standalone enqueue details from (A)SCS instance

#----

SCSID = 01

SCSHOST = scsHSP

enque/serverinst = $(SCSID)

enque/serverhost = $(SCSHOST)

#----

  1. HA polling - Only requireqd for self-control with HA polling

#----

#enque/enrep/hafunc_implementation = script

#enque/enrep/poll_interval = 10000

#enque/enrep/hafunc_init =

#enque/enrep/hafunc_check = $(DIR_EXECUTABLE)/enqtest.sh

Please Check as per my understanding Profile makes differences

Thanks

sadiq.

Former Member
‎2011 Dec 06 6:50 AM
0 Likes

> Or is it that CI and DI becomes same when ASCS in place? Because MS and ENQ is needed for entire SAP system to remain functional and these are part of ASCS which in any case is clustered and never becoming down.

>

You are right. In HA systems, message server and enq server moves to ASCS instance and ASCS instance is SPOF.

Thanks

Sunny

Former Member
‎2011 Dec 06 8:47 AM
0 Likes

Hi,

The database, enqueue, and message services in a standard SAP system cannot be maderedundant by configuring multiple instances of them on different host machines: this means that they are the single points of failure.The remaining services (that is, dialog, update, and background to be configured redundantly (in other words, on multiple host machines) to provide improved availability.

So ASCS ( has enqueue and Message server services) and DB services will act as SPOF in HA setup.

Other sap installation like central instance, dialog will help to provide improved availabiliy in a 2 node HA server setup.

Hope this helps.

Regards,

Deepak Kori

Former Member
‎2015 Jan 15 6:13 AM
0 Likes

Dear Sadiq' ji,

Thank you,

This is very useful information.

Thanks and regards,

Santosh sarkale

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