Plan your Db2 pureScale Feature installation (Linux)

Planning your Db2 pureScale Feature installation consists of writing a plan with all the tasks required before, during, and after the installation of this feature.

Installing the Db2 pureScale Feature requires that you:

Write a plan with all the tasks and details.
Perform the required prerequisite and preinstallation tasks that you specified in your plan.
Perform one of the installation methods that you chose in your plan.
Perform the required post-installation tasks indicated in your plan.
Perform any of the optional tasks.

Planning includes determining the high availability product that meets your needs, and the required network configuration and topology configurations to support them. There are different levels of pureScale installation present with the following key characteristics:

Characteristic	Description
Transport	TCP/IP: Used for lower read/write ratios Note: 100GB recommended, but 10GB can be configured for very low-write percentage with low network requirements by setting up DB2_SD_ALLOW_SLOW_NETWORK RDMA: Used for a higher Read/Write Ratio
IO Fencing	Slow IO Fencing: Used for lower recovery performance Fast IO Fencing using SCI3PR: Used for higher recovery performance
DR solution	GDPC: Used for active-active DR solution in nearby locations HADR: Used for active-passive DR solution in any location GDPC and HADR common combinations TCP/IP with Slow IO Fencing and no DR: Used for test and development environments TCP/IP with Fast IO Fencing: Used for read-heavy scenarios (read/write ratio of 95/5 and higher read percentage) Note: For more information on read/write rations, see What is the general guidance for choosing suitable storage for a Db2 pureScale workload? RDMA, Fast IO Fencing: Used for write-heavy scenarios (read/write ratios of 90/10 or higher write percentage) RDMA, Fast IO Fencing, HADR: Used for write-heavy scenarios (read/write ratios of 90/10 and higher write percentage) and active-passive DR RDMA, Fast IO Fencing, GDPC: Used for write-heavy scenarios and active-active DR solution

Characteristic

Description

Transport

TCP/IP: Used for lower read/write ratios
Note: 100GB recommended, but 10GB can be configured for very low-write percentage with low network requirements by setting up DB2_SD_ALLOW_SLOW_NETWORK
RDMA: Used for a higher Read/Write Ratio

IO Fencing

Slow IO Fencing: Used for lower recovery performance
Fast IO Fencing using SCI3PR: Used for higher recovery performance

DR solution

GDPC: Used for active-active DR solution in nearby locations
HADR: Used for active-passive DR solution in any location

GDPC and HADR common combinations
- TCP/IP with Slow IO Fencing and no DR: Used for test and development environments
- TCP/IP with Fast IO Fencing: Used for read-heavy scenarios (read/write ratio of 95/5 and higher read percentage)
  Note: For more information on read/write rations, see What is the general guidance for choosing suitable storage for a Db2 pureScale workload?
- RDMA, Fast IO Fencing: Used for write-heavy scenarios (read/write ratios of 90/10 or higher write percentage)
- RDMA, Fast IO Fencing, HADR: Used for write-heavy scenarios (read/write ratios of 90/10 and higher write percentage) and active-passive DR
- RDMA, Fast IO Fencing, GDPC: Used for write-heavy scenarios and active-active DR solution

The Db2 pureScale Feature provides continuous availability, disaster recovery, high availability, scalability, and consolidation considerations. Based on your particular environment, the type of workloads you handle, and disaster recovery requirements, Db2 provides continuous availability options to meet your specific needs:

Db2 pureScale Feature,
High availability disaster recovery (HADR) in Db2 pureScale environments.

If you have not already read about these availability options, read topic Introduction to a Db2 pureScale environment.

After determining the HA product that meets your needs, you need to review the prerequisites and pre-installation tasks to support your HA solution. These include:

Hardware support: Network configuration includes a choice of these networks:
- RDMA protocol over InfiniBand (IB) network,
- RDMA protocol over Converged Ethernet (RoCE) network, or
- TCP/IP protocol over Ethernet (TCP/IP) network.
Configuration of adapters and switches is required for IB or RoCE networks.
Associated software
- Linux® distribution, kernel version levels, and required packages for either RHEL or SLES
  - Installing the Db2 pureScale Feature using the Db2 Setup wizard requires an X Window System (X11) to display the graphical user interface (GUI).
- OFED or HPN packages
- C++ runtime level
- OpenSSH
- Db2 installer automatically installs:
  - IBM Storage Scale,
  - Pacemaker
Platform configuration
- Hardware and firmware (including cables and switches for an IB or RoCE network)
- SSH must validate access between all hosts
- Disk space required for various directories
A user name and group name (complete with passwords) is required to create the Db2 pureScale instance.

In pureScale environments, all hosts within the cluster must have the following /etc/hosts file format: <IP_Address> <fully_qualified_name> <short_name>

The following table lists all of the tasks required to ensure a successful new installation of the Db2 pureScale Feature:

Table 1.
Task	Details
Meeting the hardware, software and platform configuration prerequisites, and performing configuration preinstallation tasks	If you are using a virtual machine, ensure that you meet the virtual environment, storage, and network requirements. Review the Installation prerequisites for the Db2 pureScale environment in a virtual machine (Intel Linux). Ensure that you meet the requirements for: software prerequisites, storage hardware, and hardware and firmware (network adapters, cables, switches). Review the Installation prerequisites for Db2 pureScale Feature (Intel Linux). On an IB or RoCE network, configuration of communication adapter ports and switches is required. Review the appropriate sections in Configuring communication adapter ports and switches (Linux) (this includes network topology switch configuration). To automatically adjust kernel parameter settings, review Modifying kernel parameters (Linux). For authentication and encryption, OpenSSH needs to be installed and set up. Alternatively, to install the Db2 pureScale Feature without enabling remote root login and passwordless SSH, you can set up db2locssh. Review Installing and setting up OpenSSH, as well as, Setting up db2locssh. Shared storage devices are divided into categories that group storage devices and multipath I/O driver pairs based on fast I/O fencing and Db2 cluster services tiebreaker support. Review Shared storage support. Three users are required to create the Db2 pureScale instance. Default users and group values can be used. Review Creating required users for a DB2® pureScale Feature installation. To verify your environment, review the steps in Preinstallation checklist for Db2 pureScale Feature (Linux). Check and verify you meet the installation prerequisites. Review Checking installation prerequisites with db2prereqcheck. Advanced pre-installation tasks: IBM Storage Scale is the only supported file system. Prior to installing a Db2 pureScale environment, if your system already has IBM Storage Scale installed, you must verify your existing configuration. Review User-managed file system support for DB2 pureScale environments. You can choose to pass the ownership of your existing IBM Storage Scale file system to be managed by the Db2 pureScale environment. Review Manually allowing the DB2 installer to take over a user-managed IBM Storage Scale cluster.
Installation tasks	Choose one of these installation methods: Install in a virtual environment Install using the DB2 Setup wizard Install using the db2_install command Install using a response file
Performing post-installation tasks	Register the license certificate file (Registering the license certificate file for a Db2 pureScale environment using the db2licm and samlicm commands) If you did not create an instance during the installation, create one (Creating a Db2 pureScale instance in installations without an instance) If you did not specify a host list during installation, add any member or CF that you required (Adding new members or an additional cluster caching facility) Set up a Network Time Protocol Server using ntpd or chronyd Configure members and CFs as Network Time Protocol clients using ntpd or chronyd For faster fail-over support, you can optionally enable SCSI-3 PR (Enabling SCSI-3 Persistent Reserve for Db2 pureScale shared file systems) Verifying your Db2 pureScale Feature installation and setup (Verifying your Db2 pureScale installation and setup)