SAP NetWeaver Enqueue Replication 1 High Availability Cluster - SAP NetWeaver 7.40 and 7.50 #

The following sections focus on background information and the purpose of the document at hand.

This guide details how to:

This guide focuses on the high availability of the central services.

This guide does not address platform specific details. The solution described here is suitable for on-premises deplyoments and for public clouds. However, for details on deploying the solution in public clouds, refer also to the respective cloud provider documentation.

For SAP HANA system replication, follow the guides for the performance- or cost-optimized scenario.

This guide describes how to set up a pacemaker cluster using SUSE Linux Enterprise Server for SAP Applications 15 for the Enqueue Replication scenario. The goal is to match the SAP NW-HA-CLU 7.40 certification specifications and goals.

These goals include:

The updated certification SAP NW-HA-CLU 7.40 has redefined some of the test procedures and described new expectations how the cluster should behave in special conditions. These changes allowed us to improve the cluster architecture and to design it for easier usage and setup.

Shared SAP resources are on a central NFS server.

The SAP instances themselves are installed on a shared disk to allow switching over the file systems for proper functionality. The second need for a shared disk is that we are using the SBD for the cluster fencing mechanism STONITH.

3.2 Three systems for ASCS, ERS, database and additional SAP Instances #

 

This guide describes the installation of a distributed SAP system on three systems. In this setup, only two systems are in the cluster. The database and SAP dialog instances could also be added to the cluster by either adding the third node to the cluster or by installing the database on either of the nodes. However we recommend to install the database on a separate cluster.

Note

The cluster in this guide only manages the SAP instances ASCS and ERS, because of the focus of the SAP NW-HA-CLU 7.40 certification.

If your database is SAP HANA, we recommend to set up the performance optimized system replication scenario using our automation solution SAPHanaSR. The SAPHanaSR automation should be set up in an own two node cluster. The setup is described in a separate best practice document available at http://documentation.suse.com/sbp/sap.

Figure 1: Three systems for the certification setup #

 

Clustered machines #

 

• One machine (hacert01) for ASCS

  • Host name: sapha1as

• One machine (hacert02) for ERS

  • Host name: sapha1er

Non-Clustered machine #

 

• One machine (hacert03) for DB and DI

  • Host name: sapha1db

  • Host name: sapha1d1

  • Host name: sapha1d2

3.3 High availability for the database #

 

Depending on your needs you can also increase the availability of the database if your database is not already highly available by design.

3.3.1 SAP HANA system replication #

 

A perfect enhancement of the three node scenario described in this document is to implement an SAP HANA system replication (SR) automation.

Figure 2: One cluster for central services, one for SAP HANA SR #

 

Table 1: OS / database combinations supported with the system replication scenario #

 

SUSE Linux Enterprise Server for SAP Applications 15
Intel X86_64	IBM PowerLE
SAP HANA DATABASE 2.0	SAP HANA DATABASE 2.0

3.3.2 Simple stack #

 

Another option is to implement a second cluster for a database without system replication, aka "ANYDB". The cluster resource agent SAPInstance uses the SAPHOSTAGENT to control and monitor the database.

Figure 3: One cluster for the central services and one cluster for the ANY database #

 

Table 2: OS / database combination examples for the simple stack scenario #

 

SUSE Linux Enterprise Server for SAP Applications 15
Intel X86_64	IBM PowerLE
SAP HANA DATABASE 2.0	SAP HANA DATABASE 2.0
DB2 FOR LUW 10.5
MaxDB 7.9
ORACLE 12.1
SAP ASE 16.0 FOR BUS. SUITE

Note

The first version for SAP NetWeaver on IBMPowerLE is 7.50. The first version for SAP HANA on IBM PowerLE is 2.0. More information about supported combinations of OS and databases for SAP NetWeaver can be found at the SAP Product Availability Matrix. (SAP PAM)

3.4 Integration of SAP NetWeaver into the cluster using the cluster connector #

 

The integration of the HA cluster through the SAP control framework using the sap_suse_cluster_connector is of special interest. The sapstartsrv controls SAP instances since SAP Kernel versions 6.40. One of the classical problems running SAP instances in a highly available environment is the following: If an SAP administrator changes the status (start/stop) of an SAP instance without using the interfaces provided by the cluster software, the cluster framework will detect that as an error status. It will then bring the SAP instance into the old status by either starting or stopping the SAP instance. This can result in very dangerous situations if the cluster changes the status of an SAP instance during some SAP maintenance tasks. This new updated solution enables the central component sapstartsrv to report state changes to the cluster software, and therefore avoids the previously described dangerous situations. (See also blog article "Using sap_vendor_cluster_connector for interaction between cluster framework and sapstartsrv") (https://blogs.sap.com/2014/05/08/using-sapvendorclusterconnector-for-interaction-between-cluster-framework-and-sapstartsrv/comment-page-1/).

Figure 4: Cluster connector to integrate the cluster with the SAP start framework #

 

Note

For this scenario we are using an updated version of the sap-suse-cluster-connector. This version implements the API version 3 for the communication between the cluster framework and the sapstartsrv.

The new version of the sap-suse-cluster-connector now allows to start, stop and 'move' an SAP instance. The integration between the cluster software and the sapstartsrv also implements the option to run checks of the HA setup using either the command line tool sapcontrol or the SAP management consoles (SAP MMC or SAP MC).

3.5 Disks and partitions #

 

For all SAP file systems beside the file systems on NFS we are using XFS.

3.5.1 Shared disk for cluster ASCS and ERS #

 

The disk for the ASCS and ERS instances need to be shared and assigned to the cluster nodes hacert01 and hacert02. Beside the partitions for the file systems for the SAP instances, the disk also provides the partition to be used as SBD.

On hacert01, prepare the file systems for the shared disk. Create three partitions on the shared drive /dev/sdb:

• partition one (/dev/sdb1) for SBD (7M)

• partition two (/dev/sdb2) for the first file system (10GB) formatted with XFS

• partition three (/dev/sdb3) for the second file system (10GB) formatted with XFS

To create partitions, you can either use YaST or available command line tools. The following script can be used for non-interactive setups.

# parted -s /dev/sdb print
# # we are on the 'correct' drive, right?
# parted -s /dev/sdb mklabel gpt
# parted -s /dev/sdb mkpart primary 1049k 8388k
# parted -s /dev/sdb mkpart primary 8389k 10.7G
# parted -s /dev/sdb mkpart primary 10.7G 21.5G
# mkfs.xfs /dev/sdb2
# mkfs.xfs /dev/sdb3

For these file systems we recommend to use plain partitions to keep the cluster configuration as simple as possible. However, you can also place these file systems in separate volume groups. In that case, you need to add further cluster resources to control the logical volume groups. This is out of the scope of this setup guide.

After you have partitioned the shared disk on hacert01, you need to request a partition table rescan on hacert02.

# partprobe; fdisk -l /dev/sdb

During the SAP installation, /usr/sap/HA1/ASCS00 needs to be mounted on hacert01 and /usr/sap/HA1/ERS10 needs to be mounted on hacert02.

• hacert01: /dev/sdb2 /usr/sap/HA1/ASCS00

• hacert02: /dev/sdb3 /usr/sap/HA1/ERS10

3.5.2 Disk for DB and dialog instances (MaxDB example) #

 

The disk for the database and primary application server is assigned to hacert03. In an advanced setup, this disk should be shared between hacert03 and an optional additional node building an own cluster.

• partition one (/dev/sdb1) for SBD (7M) - not used here but a reservation for an optional second cluster

• partition two (/dev/sdb2) for the Database (60GB) formatted with XFS

• partition three (/dev/sdb3) for the second file system (10GB) formatted with XFS

• partition four (/dev/sdb4) for the third file system (10GB) formatted with XFS

To create partitions, you can either use YaST or available command line tools. The following script can be used for non-interactive setups.

# parted -s /dev/sdb print
# # we are on the 'correct' drive, right?
# parted -s /dev/sdb mklabel gpt
# parted -s /dev/sdb mkpart primary 1049k 8388k
# parted -s /dev/sdb mkpart primary 8389k 60G
# parted -s /dev/sdb mkpart primary 60G 70G
# parted -s /dev/sdb mkpart primary 70G 80G
# mkfs.xfs /dev/sdb2
# mkfs.xfs /dev/sdb3
# mkfs.xfs /dev/sdb4

To be mounted either by OS or an optional cluster #

 

• hacert03: /dev/sdb2 /sapdb

• hacert03: /dev/sdb3 /usr/sap/HA1/DVEBMGS01

• hacert03: /dev/sdb4 /usr/sap/HA1/D02

Note

D01: Since NetWeaver 7.5, the primary application server instance directory has been renamed. (D<Instance_Number>)

NFS server #

 

• nfs1:/data/nfs/suseEnqReplNW7x/HA1/sapmnt /sapmnt

• nfs1:/data/nfs/suseEnqReplNW7x/HA1/usrsapsys /usr/sap/HA1/SYS

Media #

 

• nfs1:/data/SCT/media/SAP-MEDIA/NW74 /sapcd

or

• nfs1:/data/SCT/media/SAP-MEDIA/NW75 /sapcd

192.168.201.111  hacert01
192.168.201.112  hacert02
192.168.201.113  hacert03
192.168.201.115  sapha1as
192.168.201.116  sapha1er
192.168.201.117  sapha1db
192.168.201.118  sapha1d1
192.168.201.119  sapha1d2

3.7 Mount points and NFS shares #

 

In our setup, the directory /usr/sap is part of the root file system. You can also create a dedicated file system for that area and mount /usr/sap during the system boot. As /usr/sap also contains the SAP control file sapservices and the saphostagent, the directory should not be placed on a shared file system between the cluster nodes.

Create the directory structure on all nodes which might be able to run the SAP resource. The SYS directory will be on an NFS share for all nodes.

• Creating mount points and mounting NFS share at all nodes

Example 1: SAP NetWeaver 7.4 #

 

# mkdir -p /sapcd
# mkdir -p /sapmnt
# mkdir -p /usr/sap/HA1/{ASCS00,D02,DVEBMGS01,ERS10,SYS}
# mount -t nfs nfs1:/data/nfs/suseEnqReplNW7x/HA1/sapmnt    /sapmnt
# mount -t nfs nfs1:/data/nfs/suseEnqReplNW7x/HA1/usrsapsys /usr/sap/HA1/SYS
# mount -t nfs nfs1:/data/SCT/media/SAP-MEDIA/NW74 /sapcd

Example 2: SAP NetWeaver 7.5 #

 

# mkdir -p /sapcd
# mkdir -p /sapmnt
# mkdir -p /usr/sap/HA1/{ASCS00,D01,D02,ERS10,SYS}
# mount -t nfs nfs1:/data/nfs/suseEnqReplNW7x/HA1/sapmnt    /sapmnt
# mount -t nfs nfs1:/data/nfs/suseEnqReplNW7x/HA1/usrsapsys /usr/sap/HA1/SYS
# mount -t nfs nfs1:/data/SCT/media/SAP-MEDIA/NW75 /sapcd

• Only MaxDB: creating mount points for the database at hacert03:

# mkdir -p /sapdb

• Only HANA: creating mount points for database at hacert03:

# mkdir -p /hana/{shared,data,log}

• Other databases: creating mount points based on there installation guide.

As you do not control the NFS shares via the cluster in this setup, you should add these file systems to /etc/fstab to get the file systems mounted during the next system boot.

Figure 5: File system layout including NFS shares #

 

Prepare the three servers for the distributed SAP installation. Server 1 (hacert01) will be used to install the ASCS SAP instance. Server 2 (hacert02) will be used to install the ERS SAP instance and server 3 (hacert03) will be used to install the dialog SAP instances and the database.

• Mounting the instance and database file systems at one specific node:

Example 3: SAP NetWeaver 7.40 on x86_64 architecture with MaxDB #

 

(ASCS   hacert01) # mount /dev/sdb2 /usr/sap/HA1/ASCS00
(ERS    hacert02) # mount /dev/sdb3 /usr/sap/HA1/ERS10
(DB     hacert03) # mount /dev/sdb2 /sapdb
(Dialog hacert03) # mount /dev/sdb3 /usr/sap/HA1/DVEBMGS01
(Dialog hacert03) # mount /dev/sdb4 /usr/sap/HA1/D02

Example 4: SAP NetWeaver 7.50 on PowerLE architecture with HANA #

 

(ASCS   hacert01) # mount /dev/sdb2 /usr/sap/HA1/ASCS00
(ERS    hacert02) # mount /dev/sdb3 /usr/sap/HA1/ERS10
(DB     hacert03) # mount /dev/sdc1 /hana/shared
(DB     hacert03) # mount /dev/sdc2 /hana/log
(DB     hacert03) # mount /dev/sdc3 /hana/data
(Dialog hacert03) # mount /dev/sdb3 /usr/sap/HA1/D01
(Dialog hacert03) # mount /dev/sdb4 /usr/sap/HA1/D02

• As a result, the directory /usr/sap/HA1/ should now look like:

# ls -la /usr/sap/HA1/
total 0
drwxr-xr-x 1 ha1adm sapsys 70 28. Mar 17:26 ./
drwxr-xr-x 1 root   sapsys 58 28. Mar 16:49 ../
drwxr-xr-x 7 ha1adm sapsys 58 28. Mar 16:49 ASCS00/
drwxr-xr-x 1 ha1adm sapsys  0 28. Mar 15:59 D02/
drwxr-xr-x 1 ha1adm sapsys  0 28. Mar 15:59 D01/
drwxr-xr-x 1 ha1adm sapsys  0 28. Mar 15:59 ERS10/
drwxr-xr-x 5 ha1adm sapsys 87 28. Mar 17:21 SYS/

Note

The owner of the directory and files is changed during the SAP installation. By default all of them are owned by root.

The overall procedure to install the distributed SAP is:

The result will be a distributed SAP installation as illustrated here:

Figure 6: Distributed installation of the SAP system #

 

Group sapinst      1000
Group sapsys       1001
Group sapadm       3000
Group sdba         3002

User  ha1adm       3000
User  sdb          3002
User  sqdha1       3003
User  sapadm       3004
User  h04adm       4001

# ip a a 192.168.201.115/24 dev eth0
# mount /dev/sdb2 /usr/sap/HA1/ASCS00
# cd /sapcd/SWPM/
# ./sapinst SAPINST_USE_HOSTNAME=sapha1as

# ip a a 192.168.201.116/24 dev eth0
# mount /dev/sdb3 /usr/sap/HA1/ERS10
# cd /sapcd/SWPM/
# ./sapinst SAPINST_USE_HOSTNAME=sapha1er

# chown -R ha1adm:sapsys /usr/sap/HA1/ERS10

# sapcontrol -nr 00 -function Stop    # to stop the ASCS
# sapcontrol -nr 00 -function Start   # to start the ASCS

4.4 Poststeps for ASCS and ERS #

 

4.4.1 Stopping ASCS and ERS #

 

On hacert01

# su - ha1adm
# sapcontrol -nr 00 -function Stop
# sapcontrol -nr 00 -function StopService

On hacert02

# su - ha1adm
# sapcontrol -nr 10 -function Stop
# sapcontrol -nr 10 -function StopService

4.4.2 Disabling systemd services of the ASCS and the ERS SAP instance #

 

This is mandatory for giving control over the instance to the HA cluster. See also manual pages ocf_suse_SAPStartSrv(7) and SAPStartSrv_basic_Cluster(7).

# systemctl disable SAPHA1_00.service
# systemctl stop SAPHA1_00.service
# systemctl disable SAPHA1_10.service
# systemctl stop SAPHA1_10.service

Note

Stopping these instance services will stop the SAP instance as well. Starting the instance services will not start the SAP instances.

• Check the SAP systemd integration:

# systemctl list-unit-files | grep SAP
SAPHA1_10.service disabled
SAPHA1_10.service disabled

The instance services are now disabled as required.

# systemctl list-unit-files | grep sap
saphostagent.service enabled
sapinit.service generated
saprouter.service disabled
saptune.service enabled

The mandatory saphostagent service is enabled. This is the installation default. Some more SAP related services might be enabled, for example the recommended saptune.

# cat /usr/sap/sapservices
systemctl --no-ask-password start SAPHA1_00 # sapstartsrv pf=/usr/sap/HA1/SYS/profile/HA1_ASCS00_sapha1as
systemctl --no-ask-password start SAPHA1_10 # sapstartsrv pf=/usr/sap/HA1/SYS/profile/HA1_ERS10_sapha1er

The sapservices file is still there for compatibility. It shows native systemd commands, one per line for each registered instance. You will find a SystemV style example in the appendix.

4.4.3 Integrating the cluster framework using sap-suse-cluster-connector #

 

Install the package sap-suse-cluster-connector version 3.1.0 from our repositories:

# zypper in sap-suse-cluster-connector

Note

Be careful as there are two packages available. The package sap_suse_cluster_connector continues to contain the old version 1.1.0 (SAP API 1). The package sap-suse-cluster-connector contains the new version 3.1.x (SAP API 3). The package sap-suse-cluster-connector with version 3.1.x implements the SUSE SAP API version 3. New features like SAP Rolling Kernel Switch (RKS) and the move of ASCS are only supported with this new version.

For the ERS and ASCS instance edit the instance profiles HA1_ASCS00_sapha1as and HA1_ERS10_sapha1er in the profile directory /usr/sap/HA1/SYS/profile/.

You need to tell sapstartsrv to load the HA script connector library and to use the sap-suse-cluster-connector. Additionally, make sure the feature Autostart is not used.

service/halib = $(DIR_EXECUTABLE)/saphascriptco.so
service/halib_cluster_connector = /usr/bin/sap_suse_cluster_connector

Add the user ha1adm to the unix user group haclient.

# usermod -aG haclient ha1adm

4.4.4 Adapting SAP profiles to match the SAP NW-HA-CLU 7.40 certification #

 

For the ASCS, change the start command from Restart_Program_xx to Start_Program_xx for the enqueue server (enserver). This change tells the SAP start framework not to self-restart the enqueue process. Such a restart would lead in loss of the locks.

Example 5: File /usr/sap/HA1/SYS/profile/HA1_ASCS00_sapha1as #

 

Start_Program_01 = local $(_EN) pf=$(_PF)

Optionally you can limit the number of restarts of services (in the case of ASCS this limits the restart of the message server).

For the ERS, change the start command from Restart_Program_xx to Start_Program_xx for the enqueue replication server (enrepserver).

Example 6: File /usr/sap/HA1/SYS/profile/HA1_ERS10_sapha1er #

 

Start_Program_00 = local $(_ER) pf=$(_PFL) NR=$(SCSID)

4.4.5 Starting ASCS and ERS #

 

On hacert01

# su - ha1adm
# sapcontrol -nr 00 -function StartService HA1
# sapcontrol -nr 00 -function Start

On hacert02

# su - ha1adm
# sapcontrol -nr 10 -function StartService HA1
# sapcontrol -nr 10 -function Start

# ip a a 192.168.201.117/24 dev eth0
# mount /dev/sdb2 /sapdb
# cd /sapcd/SWPM/
# ./sapinst SAPINST_USE_HOSTNAME=sapha1db

# ip a a 192.168.201.117/24 dev eth0
# mount /dev/sdc1 /hana/shared
# mount /dev/sdc2 /hana/log
# mount /dev/sdc3 /hana/data
# cd /sapcd/SWPM/
# ./sapinst SAPINST_USE_HOSTNAME=sapha1db

# ip a a 192.168.201.118/24 dev eth0
# mount /dev/sdb3 /usr/sap/HA1/DVEBMGS01
# cd /sapcd/SWPM/
# ./sapinst SAPINST_USE_HOSTNAME=sapha1d1

# ip a a 192.168.201.118/24 dev eth0
# mount /dev/sdb3 /usr/sap/HA1/D01
# cd /sapcd/SWPM/
# ./sapinst SAPINST_USE_HOSTNAME=sapha1d1

# ip a a 192.168.201.119/24 dev eth0
# mount /dev/sdb4 /usr/sap/HA1/D02
# cd /sapcd/SWPM/
# ./sapinst SAPINST_USE_HOSTNAME=sapha1d2

The main procedure to implement the cluster is as follows:

Note

Before you continue to set up the cluster, first stop all SAP instances, remove the (manually added) IP addresses on the cluster nodes and unmount the file systems which will be controlled by the cluster later.

Note

The SBD device/partition needs to be created beforehand. In this setup guide, partition /dev/sdb1 is already reserved for SBD usage.

# zypper in -t pattern ha_sles

# modprobe softdog
# echo "softdog" > /etc/modules-load.d/softdog.conf
# systemctl enable sbd
# ha-cluster-init -y -i eth0 -u -s /dev/sdb1

# modprobe softdog
# echo "softdog" > /etc/modules-load.d/softdog.conf
# systemctl enable sbd
# rsync 192.168.201.111:/etc/sysconfig/sbd /etc/sysconfig

# ha-cluster-join -y -c 192.168.201.111 -i eth0

Stack: corosync
Current DC: hacert01 (version 1.1.18+20180430.b12c320f5-1.14-b12c320f5) - partition with quorum
Last updated: Wed Apr  3 13:53:40 2019
Last change: Wed Apr  3 13:44:40 2019 by root via cibadmin on hacert01

2 nodes configured
1 resource configured

Online: [ hacert01 hacert02 ]

Full list of resources:

 stonith-sbd    (stonith:external/sbd): Started hacert01

# crm configure show
...
property cib-bootstrap-options: \
        have-watchdog=true \
        dc-version=1.1.18+20180430.b12c320f5-1.14-b12c320f5 \
        cluster-infrastructure=corosync \
        cluster-name=hacluster \
        stonith-enabled=true \
        last-lrm-refresh=1494346532
rsc_defaults rsc-options: \
        resource-stickiness=1 \
        migration-threshold=3
op_defaults op-options: \
        timeout=600 \
        record-pending=true

5.2 Configuring cluster resources #

 

You need a changed SAPInstance resource agent for SAP NetWeaver to not use the multi-state construct but to move to a more cluster-like construct, to start and stop the ASCS and the ERS itself and not the complete multi-state construct.

For this there is a new functionality for the ASCS needed to follow the ERS. The ASCS needs to mount the shared memory table of the ERS to avoid the loss of locks.

Figure 7: Resources and constraints #

 

The implementation is done using the new flag "runs_ers_$SID" within the RA, enabled using the resource parameter "IS_ERS=TRUE".

Another benefit of this concept is that you can now work with local (mountable) file systems instead of a shared (NFS) file system for the SAP instance directories.

5.2.1 Preparing the cluster for adding the resources #

 

To avoid that the cluster starts partially defined resources, set the cluster to the maintenance mode. This deactivates all monitor actions.

As user root

# crm configure property maintenance-mode="true"

5.2.2 Configuring the resources for the ASCS #

 

First, configure the resources for the file system, IP address and the SAP instance. Make sure you adapt the parameters to your environment. The shown file system and SAPInstance monitor timeouts are a trade-off between fast recovery vs. resilience against sporadic temporary NFS issues. You may slightly increase it to fit your infrastructure. The SAPInstance timeout needs to be higher than the file system timeout. Consult your storage or NFS server documentation for appropriate timeout values. See also manual pages ocf_heartbeat_Filesystem(7), ocf_heartbeat_SAPInstance(7) and nfs(5).

Example 7: ASCS primitive #

 

primitive rsc_fs_HA1_ASCS00 Filesystem \
  params device="/dev/sdb2" directory="/usr/sap/HA1/ASCS00" \
   fstype=xfs \
  op start timeout=60s interval=0 \
  op stop timeout=60s interval=0 \
  op monitor interval=20s timeout=40s
primitive rsc_ip_HA1_ASCS00 IPaddr2 \
  params ip=192.168.201.115 \
  op monitor interval=10s timeout=20s
primitive rsc_sap_HA1_ASCS00 SAPInstance \
  op monitor interval=11 timeout=60 on-fail=restart \
  params InstanceName=HA1_ASCS00_sapha1as \
   START_PROFILE="/sapmnt/HA1/profile/HA1_ASCS00_sapha1as" \
   AUTOMATIC_RECOVER=false \
  meta resource-stickiness=5000 failure-timeout=60 \
   migration-threshold=1 priority=10

Example 8: ASCS group #

 

group grp_HA1_ASCS00 \
  rsc_ip_HA1_ASCS00 rsc_fs_HA1_ASCS00 rsc_sap_HA1_ASCS00 \
	meta resource-stickiness=3000

Create a txt file (like crm_ascs.txt) with your preferred text editor, enter both examples (primitives and group) to that file and load the configuration to the cluster manager configuration.

As user root

# crm configure load update crm_ascs.txt

5.2.3 Configuring the resources for the ERS #

 

Second, configure the resources for the file system, IP address and the SAP instance. Make sure you adapt the parameters to your environment. The shown file system and SAPInstance monitor timeouts are a trade-off between fast recovery vs. resilience against sporadic temporary NFS issues. You may slightly increase it to fit your infrastructure. The SAPInstance timeout needs to be higher than the file system timeout. Consult your storage or NFS server documentation for appropriate timeout values. See also manual pages ocf_heartbeat_Filesystem(7), ocf_heartbeat_SAPInstance(7) and nfs(5).

The specific parameter IS_ERS=true should only be set for the ERS instance.

Example 9: ERS primitive #

 

primitive rsc_fs_HA1_ERS10 Filesystem \
  params device="/dev/sdb3" directory="/usr/sap/HA1/ERS10" fstype=xfs \
  op start timeout=60s interval=0 \
  op stop timeout=60s interval=0 \
  op monitor interval=20s timeout=40s
primitive rsc_ip_HA1_ERS10 IPaddr2 \
  params ip=192.168.201.116 \
  op monitor interval=10s timeout=20s
primitive rsc_sap_HA1_ERS10 SAPInstance \
  op monitor interval=11 timeout=60 on-fail=restart \
  params InstanceName=HA1_ERS10_sapha1er \
   START_PROFILE="/sapmnt/HA1/profile/HA1_ERS10_sapha1er" \
   AUTOMATIC_RECOVER=false IS_ERS=true \
  meta priority=1000

Example 10: ERS group #

 

group grp_HA1_ERS10 \
  rsc_ip_HA1_ERS10 rsc_fs_HA1_ERS10 rsc_sap_HA1_ERS10

Create a txt file (like crm_ers.txt) with your preferred text editor, enter both examples (primitives and group) to that file and load the configuration to the cluster manager configuration.

As user root

# crm configure load update crm_ers.txt

5.2.4 Configuring the colocation constraints between ASCS and ERS #

 

The constraints between the ASCS and ERS instance are needed to define that the ASCS instance starts exactly on the cluster node running the ERS instance after a failure (loc_sap_HA1_failover_to_ers). This constraint is needed to ensure that the locks are not lost after an ASCS instance (or node) failure.

If the ASCS instance has been started by the cluster, the ERS instance should be moved to an "other" cluster node (col_sap_HA1_no_both). This constraint is needed to ensure that the ERS will synchronize the locks again and the cluster is ready for an additional take-over.

Example 11: Location constraint #

 

colocation col_sap_HA1_no_both -5000: grp_HA1_ERS10 grp_HA1_ASCS00
location loc_sap_HA1_failover_to_ers rsc_sap_HA1_ASCS00 \
  rule 2000: runs_ers_HA1 eq 1
order ord_sap_HA1_first_start_ascs Optional: rsc_sap_HA1_ASCS00:start \
  rsc_sap_HA1_ERS10:stop symmetrical=false

Create a txt file (like crm_col.txt) with your preferred text editor, enter all three constraints to that file and load the configuration to the cluster manager configuration.

As user root

# crm configure load update crm_col.txt

5.2.5 Activating the cluster #

 

The last step is to end the cluster maintenance mode and to allow the cluster to detect already running resources.

As user root

# crm configure property maintenance-mode="false"

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