SAP HANA scale-out system with host auto-failover deployment guide

This guide shows you how to use Cloud Deployment Manager to deploy an SAP HANA scale-out system that includes the SAP HANA host auto-failover fault-recovery solution. By using Deployment Manager, you can deploy a system that meets SAP support requirements and adheres to both SAP and Compute Engine best practices.

The resulting SAP HANA system includes a master host, up to 15 worker hosts, and up to 3 standby hosts all within a single Compute Engine zone.

The system also includes the Google Cloud storage manager for SAP HANA standby nodes (storage manager for SAP HANA), which manages the transfer of storage devices to the standby node during a failover. The storage manager for SAP HANA is installed in the SAP HANA /shared volume.

Do not use this guide if you do not need the host auto-failover feature. Instead, use the SAP HANA Deployment Guide.

If you need to deploy SAP HANA in a Linux high-availability cluster, use on of the following guides:

This guide is intended for advanced SAP HANA users who are familiar with SAP scale-out configurations that include standby hosts for high-availability, as well as network file systems.


Before you create the SAP HANA high availability scale-out system, make sure that the following prerequisites are met:

  • You or your organization has a Google Cloud account and you have created a project for the SAP HANA deployment. For information about creating Google Cloud accounts and projects, see Setting up your Google account in the SAP HANA Deployment Guide.
  • The SAP HANA installation media is stored in a Cloud Storage bucket that is available in your deployment project and region. For information about how to upload SAP HANA installation media to a Cloud Storage bucket, see Creating a Cloud Storage bucket. in the SAP HANA Deployment Guide.
  • You have an NFS solution, such as the managed Filestore solution, for sharing the SAP HANA /hana/shared and /hanabackup volumes among the hosts in the scale-out SAP HANA system. You specify the mount points for the NFS servers in the Deployment Manager configuration file before you can deploy the system. To deploy Filestore NFS servers, see Creating instances.
  • Communication must be allowed between all VMs in the SAP HANA subnetwork that host an SAP HANA scale-out node.

  • If OS login is enabled in your project metadata , you need to disable OS login temporarily until your deployment is complete. For deployment purposes, this procedure configures SSH keys in instance metadata. When OS login is enabled, metadata-based SSH key configurations are disabled, and this deployment fails. After deployment is complete, you can enable OS login again.

    For more information, see:

Creating a network

For security purposes, create a new network. You can control who has access by adding firewall rules or by using another access control method.

If your project has a default VPC network, don't use it. Instead, create your own VPC network so that the only firewall rules in effect are those that you create explicitly.

During deployment, VM instances typically require access to the internet to download Google's monitoring agent. If you are using one of the SAP-certified Linux images that are available from Google Cloud, the VM instance also requires access to the internet in order to register the license and to access OS vendor repositories. A configuration with a NAT gateway and with VM network tags supports this access, even if the target VMs do not have external IPs.

To set up networking:

  1. Go to Cloud Shell.

    Go to Cloud Shell

  2. To create a new network in the custom subnetworks mode, run:

    gcloud compute networks create NETWORK_NAME --subnet-mode custom

    Replace NETWORK_NAME with the name of the new network. The network name can contain only lowercase characters, digits, and the dash character (-).

    Specify --subnet-mode custom to avoid using the default auto mode, which automatically creates a subnet in each Compute Engine region. For more information, see Subnet creation mode.

  3. Create a subnetwork, and specify the region and IP range:

    gcloud compute networks subnets create SUBNETWORK_NAME \
            --network NETWORK_NAME --region REGION --range RANGE

    Replace the following:

    • SUBNETWORK_NAME: the name of the new subnetwork.
    • NETWORK_NAME: the name of the network you created in the previous step.
    • REGION: the region where you want the subnetwork.
    • RANGE: the IP address range, specified in CIDR format, such as If you plan to add more than one subnetwork, assign non-overlapping CIDR IP ranges for each subnetwork in the network. Note that each subnetwork and its internal IP ranges are mapped to a single region.
  4. Optionally, repeat the previous step and add additional subnetworks.

Setting up a NAT gateway

If you need to create one or more VMs without public IP addresses, you need to use network address translation (NAT) to enable the VMs to access the internet. Use Cloud NAT, a Google Cloud distributed, software-defined managed service that lets VMs send outbound packets to the internet and receive any corresponding established inbound response packets. Alternatively, you can set up a separate VM as a NAT gateway.

To create a Cloud NAT instance for your project, see Using Cloud NAT.

After you configure Cloud NAT for your project, your VM instances can securely access the internet without a public IP address.

Adding firewall rules

By default, an implied firewall rule blocks incoming connections from outside your Virtual Private Cloud (VPC) network. To allow incoming connections, set up a firewall rule for your VM. After an incoming connection is established with a VM, traffic is permitted in both directions over that connection.

You can also create a firewall rule to allow external access to specified ports, or to restrict access between VMs on the same network. If the default VPC network type is used, some additional default rules also apply, such as the default-allow-internal rule, which allows connectivity between VMs on the same network on all ports.

Depending on the IT policy that is applicable to your environment, you might need to isolate or otherwise restrict connectivity to your database host, which you can do by creating firewall rules.

Depending on your scenario, you can create firewall rules to allow access for:

  • The default SAP ports that are listed in TCP/IP of All SAP Products.
  • Connections from your computer or your corporate network environment to your Compute Engine VM instance. If you are unsure of what IP address to use, talk to your company's network administrator.
  • Communication between VMs in the SAP HANA subnetwork, including communication between nodes in an SAP HANA scale-out system or communication between the database server and application servers in a 3-tier architecture. You can enable communication between VMs by creating a firewall rule to allow traffic that originates from within the subnetwork.

To create a firewall rule:


  1. In the Cloud Console, go to the Firewall rules page.


  2. At the top of the page, click Create firewall rule.

    • In the Network field, select the network where your VM is located.
    • In the Targets field, specify the resources on Google Cloud that this rule applies to. For example, specify All instances in the network. Or to to limit the rule to specific instances on Google Cloud, enter tags in Specified target tags.
    • In the Source filter field, select one of the following:
      • IP ranges to allow incoming traffic from specific IP addresses. Specify the range of IP addresses in the Source IP ranges field.
      • Subnets to allow incoming traffic from a particular subnetwork. Specify the subnetwork name in the following Subnets field. You can use this option to allow access between the VMs in a 3-tier or scaleout configuration.
    • In the Protocols and ports section, select Specified protocols and ports and enter tcp:[PORT_NUMBER].
  3. Click Create to create your firewall rule.


Create a firewall rule by using the following command:

$ gcloud compute firewall-rules create firewall-name
--direction=INGRESS --priority=1000 \
--network=network-name --action=ALLOW --rules=protocol:port \
--source-ranges ip-range --target-tags=network-tags

Creating an SAP HANA scale-out system with standby hosts

In the following instructions, you complete the following actions:

  • Create the SAP HANA system by invoking Deployment Manager with a configuration file template that you complete.
  • Verify deployment.
  • Test the standby host(s) by simulating a host failure.

Some of the steps in the following instructions use Cloud Shell to enter the gcloud commands. If you have the latest version of Cloud SDK installed, you can enter the gcloud commands from a local terminal instead.

Define and create the SAP HANA system

In the following steps, you download and complete a Deployment Manager configuration file template and invoke Deployment Manager, which deploys the VMs, persistent disks, and SAP HANA instances.

  1. Confirm that your current quotas for project resources, such as persistent disks and CPUs, are sufficient for the SAP HANA system you are about to install. If your quotas are insufficient, deployment fails. For the SAP HANA quota requirements, see Pricing and quota considerations for SAP HANA.

    Go to the quotas page

  2. Open Cloud Shell.

    Go to Cloud Shell

  3. Download the template.yaml configuration file template for the SAP HANA high-availability scale-out system to your working directory:

  4. Optionally, rename the template.yaml file to identify the configuration it defines. For example, you could use a file name like hana2sp3rev30-scaleout.yaml.

  5. Open the template.yaml file in the Cloud Shell code editor.

    To open the Cloud Shell code editor, click the pencil icon in the upper right corner of the Cloud Shell terminal window.

  6. In the template.yaml file, update the following property values by replacing the brackets and their contents with the values for your installation. For example, you might replace "[ZONE]" with "us-central1-f".

    Property Data type Description
    type String

    Specifies the location, type, and version of the Deployment Manager template to use during deployment.

    The YAML file includes two type specifications, one of which is commented out. The type specification that is active by default specifies the template version as latest. The type specification that is commented out specifies a specific template version with a timestamp.

    If you need all of your deployments to use the same template version, use the type specification that includes the timestamp.

    instanceName String The name of the VM instance for the SAP HANA master host. The name must be specified in lowercase letters, numbers, or hyphens. The VM instances for the worker and standby hosts use the same name with a "w" and the host number appended to the name.
    instanceType String The type of Compute Engine virtual machine that you need to run SAP HANA on. If you need a custom VM type, specify a predefined VM type with a number of vCPUs that is closest to the number you need while still being larger. After deployment is complete, modify the number of vCPUs and the amount of memory.
    zone String The zone in which you are deploying your SAP HANA systems to run. It must be in the region that you selected for your subnet.
    subnetwork String The name of the subnetwork you created in a previous step. If you are deploying to a shared VPC, specify this value as [SHAREDVPC_PROJECT]/[SUBNETWORK]. For example, myproject/network1.
    linuxImage String The name of the Linux operating-system image or image family that you are using with SAP HANA. To specify an image family, add the prefix family/ to the family name. For example, family/rhel-8-1-sap-ha or family/sles-15-sp2-sap. To specify a specific image, specify only the image name. For the list of available image families, see the Images page in the Cloud Console.
    linuxImageProject String The Google Cloud project that contains the image you are going to use. This project might be your own project or a Google Cloud image project. For a Compute Engine image, specify either rhel-sap-cloud or suse-sap-cloud. To find the image project for your operating system, see Operating system details.
    sap_hana_deployment_bucket String The name of the Cloud Storage bucket in your project that contains the SAP HANA installation files that you uploaded in a previous step.
    sap_hana_sid String The SAP HANA system ID. The ID must consist of 3 alphanumeric characters and begin with a letter. All letters must be uppercase.
    sap_hana_instance_number Integer The instance number, 0 to 99, of the SAP HANA system. The default is 0.
    sap_hana_sidadm_password String A temporary password for the operating system administrator to be used during deployment. Passwords must be at least 8 characters and include at least 1 uppercase letter, 1 lowercase letter, and 1 number.
    sap_hana_system_password String A temporary password for the database superuser to be used during deployment. Passwords must be at least 8 characters and include at least 1 uppercase letter, 1 lowercase letter, and 1 number.
    sap_hana_worker_nodes Integer The number of additional SAP HANA worker hosts that you need. You can specify 1 to 15 worker hosts. The default is value is 1.
    sap_hana_standby_nodes Integer The number of additional SAP HANA standby hosts that you need. You can specify 1 to 3 standby hosts. The default value is 1.
    sap_hana_shared_nfs String The NFS mount point for the /hana/shared volume. For example,
    sap_hana_backup_nfs String The NFS mount point for the /hanabackup volume. For example,
    networkTag String Optional. One or more comma-separated network tags that represents your VM instance for firewall or routing purposes. If you specify publicIP: No and do not specify a network tag, be sure to provide another means of access to the internet.
    publicIP Boolean Optional. Determines whether a public IP address is added to your VM instance. The default is Yes.
    sap_hana_double_volume_size Integer Optional. Doubles the HANA volume size. Useful if you wish to deploy multiple SAP HANA instances or a disaster recovery SAP HANA instance on the same VM. By default, the volume size is automatically calculated to be the minimum size required for your memory footprint, while still meeting the SAP certification and support requirements.
    sap_hana_sidadm_uid Integer Optional. Overrides the default value of the [SID]adm user ID. The default value is 900. You can change this to a different value for consistency within your SAP landscape.
    sap_hana_sapsys_gid Integer Optional. Overrides the default group ID for sapsys. The default is 79.
    sap_deployment_debug Boolean Optional. If this value is set to Yes, the deployment generates verbose deployment logs. Do not turn this setting on unless a Google support engineer asks you to enable debugging.
    post_deployment_script Boolean Optional. The URL or storage location of a script to run after the deployment is complete. The script should be hosted on a web server or in a Cloud Storage bucket. Begin the value with http:// https:// or gs://. Note that this script will be executed on all VMs that the template creates. If you only want to run it on the master instance, you will need to add a check at the top of your script.

    The following example shows a completed configuration file that deploys an SAP HANA scale-out system with three worker hosts and one standby host in the us-central1-f zone. Each host is installed on an n2-highmem-32 VM that is running a Linux operating system provided by a Compute Engine public image. The NFS volumes are provided by Filestore. Temporary passwords are used during deployment and configuration processing only. The custom service account that is specified will become the service account of the deployed VMs.

    - name: sap_hana_ha_scaleout
      # By default, this configuration file uses the latest release of the deployment
      # scripts for SAP on Google Cloud.  To fix your deployments to a specific release
      # of the scripts, comment out the type property above and uncomment the type property below.
      # type:
        instanceName: hana-scaleout-w-failover
        instanceType: n2-highmem-32
        zone: us-central1-f
        subnetwork: example-sub-network-sap
        linuxImage: family/sles-15-sp2-sap
        linuxImageProject: suse-sap-cloud
        sap_hana_deployment_bucket: hana2-sp5-rev53
        sap_hana_sid: HF0
        sap_hana_instance_number: 00
        sap_hana_sidadm_password: TempPa55word
        sap_hana_system_password: TempPa55word
        sap_hana_worker_nodes: 3
        sap_hana_standby_nodes: 1
  7. Create the instances:

    gcloud deployment-manager deployments create [DEPLOYMENT_NAME] --config [TEMPLATE_NAME].yaml

    The above command invokes the Deployment Manager, which sets up the Google Cloud infrastructure and then invokes another script that configures the operating system and installs SAP HANA.

    While Deployment Manager has control, status messages are written to the Cloud Shell. After the scripts are invoked, status messages are written to Logging and are viewable in the Cloud Console, as described in Checking the Logging logs.

    Time to completion can vary, but the entire process usually takes less than 30 minutes.

Verifying deployment

To verify deployment, you check the deployment logs in Cloud Logging, check the disks and services on the VMs of the primary and worker hosts, display the system in SAP HANA Studio, and test the takeover by a standby host.

Check the logs

  1. In the Cloud Console, open Cloud Logging to monitor installation progress and check for errors.

    Go to Cloud Logging

  2. Filter the logs:

    Logs Explorer

    1. In the Logs Explorer page, go to the Query pane.

    2. From the Resource drop-down menu, select Global, and then click Add.

      If you don't see the Global option, then in the query editor, enter the following query:

    3. Click Run query.

    Legacy Logs Viewer

    • In the Legacy Logs Viewer page, from the basic selector menu, select Global as your logging resource.
    • If "--- Finished" is displayed, then the Deployment Manager processing is complete and you can proceed to the next step.

    • If you see a quota error:

      1. On the IAM & Admin Quotas page, increase any of your quotas that do not meet the SAP HANA requirements that are listed in the SAP HANA planning guide.

      2. On the Deployment Manager Deployments page, delete the deployment to clean up the VMs and persistent disks from the failed installation.

      3. Rerun the Deployment Manager.

Connect to the VMs to check the disks and SAP HANA services

After deployment is complete, confirm that the disks and SAP HANA services have deployed properly by checking the disks and services of the master host and one worker host.

  1. On the Compute Engine VM instances page, connect to the VM of the master host and the VM of one worker host by clicking the SSH button on the row of each of the two VM instances.

    Go to VM instances

    When connecting to the worker host, make sure that you aren't connecting to a standby host. The standby hosts use the same naming convention as the worker hosts, but have the highest numbered worker-host suffix before the first takeover. For example, if you have three worker hosts and one standby host, before the first takeover the standby host has a suffix of "w4".

  2. In each terminal window, switch to the root user.

    sudo su -
  3. In each terminal window, display the disk file system.

    df -h

    On the master host, you should see output similar to the following.

    hana-scaleout-w-failover:~ # df -h
    Filesystem                Size  Used Avail Use% Mounted on
    devtmpfs                  126G  8.0K  126G   1% /dev
    tmpfs                     189G     0  189G   0% /dev/shm
    tmpfs                     126G   18M  126G   1% /run
    tmpfs                     126G     0  126G   0% /sys/fs/cgroup
    /dev/sda3                  45G  5.6G   40G  13% /
    /dev/sda2                  20M  2.9M   18M  15% /boot/efi  1007G   50G  906G   6% /hana/shared
    tmpfs                      26G     0   26G   0% /run/user/473 1007G     0  956G   0% /hanabackup
    tmpfs                      26G     0   26G   0% /run/user/900
    /dev/mapper/vg_hana-data  709G  7.7G  702G   2% /hana/data/HF0/mnt00001
    /dev/mapper/vg_hana-log   125G  5.3G  120G   5% /hana/log/HF0/mnt00001
    tmpfs                      26G     0   26G   0% /run/user/1003

    On a worker host, notice that the /hana/data and /hana/log directories have different mounts.

    hana-scaleout-w-failoverw2:~ # df -h
    Filesystem                Size  Used Avail Use% Mounted on
    devtmpfs                  126G  8.0K  126G   1% /dev
    tmpfs                     189G     0  189G   0% /dev/shm
    tmpfs                     126G  9.2M  126G   1% /run
    tmpfs                     126G     0  126G   0% /sys/fs/cgroup
    /dev/sda3                  45G  5.6G   40G  13% /
    /dev/sda2                  20M  2.9M   18M  15% /boot/efi
    tmpfs                      26G     0   26G   0% /run/user/0  1007G   50G  906G   6% /hana/shared 1007G     0  956G   0% /hanabackup
    /dev/mapper/vg_hana-data  709G  821M  708G   1% /hana/data/HF0/mnt00003
    /dev/mapper/vg_hana-log   125G  2.2G  123G   2% /hana/log/HF0/mnt00003
    tmpfs                      26G     0   26G   0% /run/user/1003

    On a standby host, the data and log directories are not mounted until the standby host takes over for a failed host.

    hana-scaleout-w-failoverw4:~ # df -h
    Filesystem                Size  Used Avail Use% Mounted on
    devtmpfs                  126G  8.0K  126G   1% /dev
    tmpfs                     189G     0  189G   0% /dev/shm
    tmpfs                     126G   18M  126G   1% /run
    tmpfs                     126G     0  126G   0% /sys/fs/cgroup
    /dev/sda3                  45G  5.6G   40G  13% /
    /dev/sda2                  20M  2.9M   18M  15% /boot/efi
    tmpfs                      26G     0   26G   0% /run/user/0  1007G   50G  906G   6% /hana/shared 1007G     0  956G   0% /hanabackup
    tmpfs                      26G     0   26G   0% /run/user/1003
  4. In each terminal window, change to the SAP HANA operating system user. Replace SID with the SID value that you specified in the configuration file template.

    su - SIDadm
  5. In each terminal window, ensure that SAP HANA services, such as hdbnameserver, hdbindexserver, and others, are running on the instance.

    HDB info

    On the master host, you should see output similar to the output in the following truncated example:

    hf0adm@hana-scaleout-w-failover:/usr/sap/HF0/HDB00> HDB info
    USER          PID     PPID  %CPU        VSZ        RSS COMMAND
    hf0adm       5936     5935   0.7      18540       6776 -sh
    hf0adm       6011     5936   0.0      14128       3856  \_ /bin/sh /usr/sap/HF0/HDB00/HDB info
    hf0adm       6043     6011   0.0      34956       3568      \_ ps fx -U hf0adm -o user:8,pid:8,ppid:8,pcpu:5,vsz:10
    hf0adm      17950        1   0.0      23052       3168 sapstart pf=/hana/shared/HF0/profile/HF0_HDB00_hana-scaleout
    hf0adm      17957    17950   0.0     457332      70956  \_ /usr/sap/HF0/HDB00/hana-scaleout-w-failover/trace/
    hf0adm      17975    17957   1.8    9176656    3432456      \_ hdbnameserver
    hf0adm      18334    17957   0.4    4672036     229204      \_ hdbcompileserver
    hf0adm      18337    17957   0.4    4941180     257348      \_ hdbpreprocessor
    hf0adm      18385    17957   4.5    9854464    4955636      \_ hdbindexserver -port 30003
    hf0adm      18388    17957   1.2    7658520    1424708      \_ hdbxsengine -port 30007
    hf0adm      18865    17957   0.4    6640732     526104      \_ hdbwebdispatcher
    hf0adm      14230        1   0.0     568176      32100 /usr/sap/HF0/HDB00/exe/sapstartsrv pf=/hana/shared/HF0/profi
    hf0adm      10920        1   0.0     710684      51560 hdbrsutil  --start --port 30003 --volume 3 --volumesuffix mn
    hf0adm      10575        1   0.0     710680      51104 hdbrsutil  --start --port 30001 --volume 1 --volumesuffix mn
    hf0adm      10217        1   0.0      72140       7752 /usr/lib/systemd/systemd --user
    hf0adm      10218    10217   0.0     117084       2624  \_ (sd-pam)

    On a worker host, you should see output similar to the output in the following truncated example:

    hf0adm@hana-scaleout-w-failoverw2:/usr/sap/HF0/HDB00> HDB info
    USER          PID     PPID  %CPU        VSZ        RSS COMMAND
    hf0adm      22136    22135   0.3      18540       6804 -sh
    hf0adm      22197    22136   0.0      14128       3892  \_ /bin/sh /usr/sap/HF0/HDB00/HDB info
    hf0adm      22228    22197   100      34956       3528      \_ ps fx -U hf0adm -o user:8,pid:8,ppid:8,pcpu:5,vsz:10
    hf0adm       9138        1   0.0      23052       3064 sapstart pf=/hana/shared/HF0/profile/HF0_HDB00_hana-scaleout
    hf0adm       9145     9138   0.0     457360      70900  \_ /usr/sap/HF0/HDB00/hana-scaleout-w-failoverw2/trace/hdb.
    hf0adm       9163     9145   0.7    7326228     755772      \_ hdbnameserver
    hf0adm       9336     9145   0.5    4670756     226972      \_ hdbcompileserver
    hf0adm       9339     9145   0.6    4942460     259724      \_ hdbpreprocessor
    hf0adm       9385     9145   2.0    7977460    1666792      \_ hdbindexserver -port 30003
    hf0adm       9584     9145   0.5    6642012     528840      \_ hdbwebdispatcher
    hf0adm       8226        1   0.0     516532      52676 hdbrsutil  --start --port 30003 --volume 5 --volumesuffix mn
    hf0adm       7756        1   0.0     567520      31316 /hana/shared/HF0/HDB00/exe/sapstartsrv pf=/hana/shared/HF0/p

    On a standby host, you should see output similar to the output in the following truncated example:

    hana-scaleout-w-failoverw4:~ # su - hf0adm
    hf0adm@hana-scaleout-w-failoverw4:/usr/sap/HF0/HDB00> HDB info
    USER          PID     PPID  %CPU        VSZ        RSS COMMAND
    hf0adm      19926    19925   0.2      18540       6748 -sh
    hf0adm      19987    19926   0.0      14128       3864  \_ /bin/sh /usr/sap/HF0/HDB00/HDB info
    hf0adm      20019    19987   0.0      34956       3640      \_ ps fx -U hf0adm -o user:8,pid:8,ppid:8,pcpu:5,vsz:10
    hf0adm       8120        1   0.0      23052       3232 sapstart pf=/hana/shared/HF0/profile/HF0_HDB00_hana-scaleout
    hf0adm       8127     8120   0.0     457348      71348  \_ /usr/sap/HF0/HDB00/hana-scaleout-w-failoverw4/trace/hdb.
    hf0adm       8145     8127   0.6    7328784     708284      \_ hdbnameserver
    hf0adm       8280     8127   0.4    4666916     223892      \_ hdbcompileserver
    hf0adm       8283     8127   0.4    4939904     256740      \_ hdbpreprocessor
    hf0adm       8328     8127   0.4    6644572     534044      \_ hdbwebdispatcher
    hf0adm       7374        1   0.0     633568      31520 /hana/shared/HF0/HDB00/exe/sapstartsrv pf=/hana/shared/HF0/p

Connect SAP HANA Studio

  1. Connect to the master SAP HANA host from SAP HANA Studio.

    You can connect from an instance of SAP HANA Studio that is outside of Google Cloud or from an instance on Google Cloud. You might need to enable network access between the target VMs and SAP HANA Studio.

    To use SAP HANA Studio on Google Cloud and enable access to the SAP HANA system, see Installing SAP HANA Studio on a Compute Engine Windows VM.

  2. In SAP HANA Studio, click the Landscape tab on the default system administration panel. You should see a display similar to the following example.

    Screenshot of the Landscape view in SAP HANA Studio

If any of the validation steps show that the installation failed:

  1. Correct the error.
  2. On the Deployments page, delete the deployment.
  3. Rerun your deployment.

Performing a failover test

After you have confirmed that the SAP HANA system deployed successfully, test the failover function.

The following instructions trigger a failover by switching to the SAP HANA operating system user and entering the HDB stop command. The HDB stop command initiates a graceful shutdown of SAP HANA and detaches the disks from the host, which enables a relatively quick failover.

To perform a failover test:

  1. Connect to the VM of a worker host by using SSH. You can connect from the Compute Engine VM instances page by clicking the SSH button for each VM instance, or you can use your preferred SSH method.

    Go to VM instances

  2. Change to the SAP HANA operating system user. In the following example, replace "[SID]" with the SID that you defined for your system.

    su - [SID]adm
  3. Simulate a failure by stopping SAP HANA:

    HDB stop

    The HDB stop command initiates a shutdown of SAP HANA, which triggers a failover. During the failover, the disks are detached from the failed host and reattached to the standby host. The failed host is restarted and becomes a standby host.

  4. After allowing time for the takeover to complete, reconnect to the host that took over for the failed host by using SSH.

  5. Change to the root user.

    sudo su -
  6. Display the disk file system of the VMs for the master and worker hosts.

    df -h

    You should see output similar to the following. The /hana/data and /hana/log directories from the failed host are now mounted to the host that took over.

    hana-scaleout-w-failoverw4:~ # df -h
    Filesystem                Size  Used Avail Use% Mounted on
    devtmpfs                  126G  8.0K  126G   1% /dev
    tmpfs                     189G     0  189G   0% /dev/shm
    tmpfs                     126G  9.2M  126G   1% /run
    tmpfs                     126G     0  126G   0% /sys/fs/cgroup
    /dev/sda3                  45G  5.6G   40G  13% /
    /dev/sda2                  20M  2.9M   18M  15% /boot/efi
    tmpfs                      26G     0   26G   0% /run/user/0   1007G   50G  906G   6% /hana/shared 1007G     0  956G   0% /hanabackup
    /dev/mapper/vg_hana-data  709G  821M  708G   1% /hana/data/HF0/mnt00003
    /dev/mapper/vg_hana-log   125G  2.2G  123G   2% /hana/log/HF0/mnt00003
    tmpfs                      26G     0   26G   0% /run/user/1003
  7. In SAP HANA Studio, open the Landscape view of the SAP HANA system to confirm that the failover over was successful:

    • The status of the hosts involved in the failover should be INFO.
    • The Index Server Role (Actual) column should show the failed host as the new standby host.

    Screenshot of the Landscape view in SAP HANA Studio

Optional: enable SAP HANA Fast Restart

Google Cloud recommends enabling SAP HANA Fast Restart for each instance of SAP HANA, especially for larger instances.

As configured by Deployment Manager, the operating system and kernel settings already support SAP HANA Fast Restart. You need to define the tmpfs file system and configure SAP HANA.

For the complete authoritative instructions for SAP HANA Fast Restart, see the SAP HANA Fast Restart Option documentation.

Configure the tmpfs file system

After the host VMs and the base SAP HANA systems are successfully deployed, you need to create and mount directories for the NUMA nodes in the tmpfs file system.

Display the NUMA topology of your VM

Before you can map the required tmpfs file system, you need to know how many NUMA nodes your VM has. To display the available NUMA nodes on a Compute Engine VM, enter the following command:

lscpu | grep NUMA

For example, an m2-ultramem-208 VM type has four NUMA nodes, numbered 0-3, as shown in the following example:

NUMA node(s):        4
NUMA node0 CPU(s):   0-25,104-129
NUMA node1 CPU(s):   26-51,130-155
NUMA node2 CPU(s):   52-77,156-181
NUMA node3 CPU(s):   78-103,182-207

Create the NUMA node directories

Create a directory for each NUMA node in your VM and set the permissions.

For example, for four NUMA nodes that are numbered 0-3:

mkdir -pv /hana/tmpfs{0..3}/SID
chown -R SIDadm:sapsys /hana/tmpfs*/SID
chmod 777 -R /hana/tmpfs*/SID

Mount the NUMA node directories to tmpfs

Mount the tmpfs file system directories and specify a NUMA node preference for each with mpol=prefer:

mount tmpfsSID0 -t tmpfs -o mpol=prefer:0 /hana/tmpfs0/SID
mount tmpfsSID1 -t tmpfs -o mpol=prefer:1 /hana/tmpfs1/SID
mount tmpfsSID2 -t tmpfs -o mpol=prefer:2 /hana/tmpfs2/SID
mount tmpfsSID3 -t tmpfs -o mpol=prefer:3 /hana/tmpfs3/SID

Update /etc/fstab

To ensure that the mount points are available after an operating system reboot, add entries into the file system table, /etc/fstab:

tmpfsSID0 /hana/tmpfs0/SID tmpfs rw,relatime,mpol=prefer:0
tmpfsSID1 /hana/tmpfs1/SID tmpfs rw,relatime,mpol=prefer:1
tmpfsSID1 /hana/tmpfs2/SID tmpfs rw,relatime,mpol=prefer:2
tmpfsSID1 /hana/tmpfs3/SID tmpfs rw,relatime,mpol=prefer:3

Optional: set limits on memory usage

The tmpfs file system can grow and shrink dynamically.

To limit the memory used by the tmpfs file system, you can set a size limit for a NUMA node volume with the size option. For example:

mount tmpfsSID0 -t tmpfs -o mpol=prefer:0,size=250G /hana/tmpfs0/SID

You can also limit overall tmpfs memory usage for all NUMA nodes for a given SAP HANA instance and a given server node by setting the persistent_memory_global_allocation_limit parameter in the [memorymanager] section of the global.ini file.

SAP HANA configuration for Fast Restart

To configure SAP HANA for Fast Restart, update the global.ini file and specify the tables to store in persistent memory.

Update the [persistence] section in the global.ini file

Configure the [persistence] section in the SAP HANA global.ini file to reference the tmpfs locations. Separate each tmpfs location with a semicolon:

basepath_datavolumes = /hana/data
basepath_logvolumes = /hana/log
basepath_persistent_memory_volumes = /hana/tmpfs0/SID;/hana/tmpfs1/SID;/hana/tmpfs2/SID;/hana/tmpfs3/SID

The preceding example specifies four memory volumes for four NUMA nodes, which corresponds to the m2-ultramem-208. If you were running on the m2-ultramem-416, you would need to configure eight memory volumes (0..7).

Restart SAP HANA after modifying the global.ini file.

SAP HANA can now use the tmpfs location as persistent memory space.

Specify the tables to store in persistent memory

Specify specific column tables or partitions to store in persistent memory.

For example, to turn on persistent memory for an existing table, execute the SQL query:

ALTER TABLE exampletable persistent memory ON immediate CASCADE

To change the default for new tables add the parameter table_default in the indexserver.ini file. For example:

table_default = ON

For more information on how to control columns, tables and which monitoring views provide detailed information, see SAP HANA Persistent Memory.

Setting up the monitoring agent for SAP HANA

Optionally, you can set up the Google Cloud monitoring agent for SAP HANA, which collects metrics from SAP HANA and sends them to Cloud Monitoring. Cloud Monitoring allows you to create dashboards for your metrics, set up custom alerts based on metric thresholds, and more. For more information on setting up and configuring the monitoring agent for SAP HANA, see the Monitoring agent for SAP HANA V2.0 installation and operation guide.

Connecting to SAP HANA

Note that because these instructions don't use an external IP for SAP HANA, you can only connect to the SAP HANA instances through the bastion instance using SSH or through the Windows server using SAP HANA Studio.

  • To connect to SAP HANA through the bastion instance, connect to the bastion host, and then to the SAP HANA instance(s) by using an SSH client of your choice.

  • To connect to the SAP HANA database through SAP HANA Studio, use a remote desktop client to connect to the Windows Server instance. After connection, manually install SAP HANA Studio and access your SAP HANA database.

Performing post-deployment tasks

Before using your SAP HANA instance, we recommend that you perform the following post-deployment steps. For more information, see SAP HANA Installation and Update Guide.

  1. Change the temporary passwords for the SAP HANA system administrator and database superuser.

  2. Update the SAP HANA software with the latest patches.

  3. Install any additional components such as Application Function Libraries (AFL) or Smart Data Access (SDA).

  4. If you are upgrading an existing SAP HANA system, load the data from the existing system either by using standard backup and restore procedures or by using SAP HANA system replication.

  5. Configure and backup your new SAP HANA database. For more information, see the SAP HANA operations guide.

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