Definitive Guide to IBM Licensing for Hot, Warm and Cold Standby Machines

Definitive Guide to IBM Licensing for Hot, Warm and Cold Standby Machines
“*IBM License Tip* Reduce your IBM license costs by demonstrating your backup is not a Hot Standby”


When it comes to reducing your IBM licensing costs one of the easiest ways to reduce the number of licenses required and your S&S renewal is to take advantage of the “free” licenses available for Warm and Cold standby servers. This particular license optimisation has such a high impact because applications that need a warm or cold standby solution typically require expensive licenses.  Couple this with how easy it is to make the required changes and you have a fantastic target to reduce IT costs.


Depending on the IBM product and the status of the server it is deployed on there can be a range of licensing options. Some options are more expensive than others.  When a server has been designated a standby there’s often an opportunity to significantly reduce your license costs depending on whether the deployment meets the criteria for hot, warm or cold standby.

What are Hot, Warm and Cold standby servers?

Standby servers are full copies of a virtual or physical server including the applications deployed on them.  They sit in the background, ready to be “taken over” in the event of a problem with the primary server.  The temperature scale, hot, warm and cold, indicates how quickly the switch over will be, the level of automation and how current the data is.

What is the IBM policy on licensing Hot, Warm and Cold Standby Servers

When you search (google) for the “IBM policy on licensing Hot, Warm and Cold Standby Servers” you may be confused.  You’ll eventually find a document IBM Software Licensed under the IPLA – Backup Use Defined that hasn’t been updated since February 2003.  The font and lack of IBM branding on the document will not reassure you either but you have the right policy. If you want to be more confident you have the right policy you can find it on the IBM website. Steps to finding it are:

Do I need IBM licenses for Standby machines?

In most cases (see exceptions) you only need to get IBM license for products running on Hot Standby machines. Warm and Cold standby machines are frequently, but not always, license free so long as the production instance is fully licensed. There are certain criteria that must be met before IBM or their auditor will accept the server qualifies as warm or cold standby. If you can meet these criteria you can significantly reduce your licenses costs.

What does IBM mean by a server “doing work”

For a server to be even considered a standby it must not be “doing work”. It must be only used in the event of a disaster recovery situation. “Doing work” includes, but is not limited to activities such as:

  • Programming
  • Development
  • Program maintenance
  • Testing
  • Mirroring of transactions
  • Updating of files
  • Synchronization of programs, data, or other resources (for example, active linking with another machine, program, database, or other resource, and so on)
  • Any activity or configurations that would allow an active hot switch or other synchronized switch over between programs, databases, or other resources to occur.

If a server is “doing work” it will require a license.

What is the IBM license rules for Hot, Warm and Cold standby?

To avoid licensing servers that are warm or cold standbys you need to be clear on the rules.  IBM have published a policy which can be found on their website called Hot/Warm/Cold Backup Solution Definitions and Policy for Disaster Recovery Testing.  This describes their definition of Hot, Warm and Cold standby.

Hot Standby (Active-Active)

If production data can be accessed at the same time (concurrently) from servers in a cluster then it’s considered a Hot Standby and they need to be licensed.  By default, a standby solution is considered a Hot Standby unless you state otherwise. Active-Active replication solutions would be a common example of Hot Standby.

Warm Standby (Active-Passive)

The rule of thumb is that the role swap must be manual, the production data cannot be accessed by the standby server. It is worth reading the specific wording from the policy here as this is the area of most contention in an audit:

Production data is either switched between or replicated between storage subsystems in a cluster, and the switched or replicated data cannot be accessed by secondary nodes in the cluster until a fail-over or role-swap event occurs, at which time a secondary node becomes the production node and the production node no longer has access to the production data. Such configurations can support point-in-time copies of the production data which can be used for off-line backup operations and/or for non-production exercises such as disaster recovery compliance testing. A warm backup solution typically has an active standby operating system installed on each of the secondary nodes in the cluster for the purpose of health monitoring.

Examples of warm backup solutions are shared-storage active-passive clustering topologies.


In order to differentiate between hot standby and warm standby servers, a rule of thumb that is often applied during audits is to ask the question whether the failover mechanism is fully automated, or whether it required manual intervention. Fully automated failover mechanisms are typically able to replace the primary machine with the secondary machine in a matter of seconds. In these cases, both machines (primary and secondary) need to be licensed. On the other hand, failover mechanisms which require manual intervention will usually take minutes, or hours, to complete. In these cases, the secondary server will often be considered warm standby and therefore free of charge.

Cold Standby

If you need to start up the server or the IBM product then the machine is considered a cold standby. It does not require a license.

How do I calculate the IBM licenses needed for Hot Standby?

In simple terms, the Hot Standby must be licensed like any production instance.  Checking points include:

  • The hot standby machine must be licensed for the same IBM products as Production.
  • License metric must be the same as Production (typically PVU).
  • The number of licenses for the standby machine must cover all available cores.
  • All nodes in a hot standby configuration must be licensed
  • Sub-capacity licensing rules can be applied where standby machines are virtualised
  • Check License Information for exceptions, especially for infrastructure products (database, middleware, etc.

High Availability and Idle Standby licensing

High availability and Idle standby are special cases of a hot standby.  The default is a full production license. Depending on the product there may be a lower cost option specific to HA or Idle Standby.  WebSphere and MQ products very often have these licensing options. There are scenarios where you can argue that the Idle standby is in fact warm or cold but this is product specific and beyond the scope of this article.

Exceptions to the IBM license for Warm and Cold standby servers

There are a few exceptions to the warm, cold standby licensing rules.

IBM Products with fixed or minimum licenses for Warm and Cold Standby

Some products can have a fixed license or minimum license requirements. For DB2 the warm/idle standby server normally requires 100 PVUs per server. Others may have a minimum per core. You need to check the specific version of the product on the IBM website (license information) looking for an mention of license minimums.

Specific Exclusion to Warm and Cold standby

As IBM products evolve the entitlement rules change with each version.  Historical warm and cold standby servers did not require an additional license but this could change with a new version of a specific product.  You will need to check for the specific version deployed in case an exclusions or constraint have been added.

Cold standby server if there’s no production server.

You can have a scenario where there is a secondary server, but there is no primary server. Typically when the primary system has been decommissioned and the secondary has been forgotten (abandoned). This is a grey area but can be leverage during audits if you have enough evidence to show it was a standby and is not “doing work”. Expect push back.

Backup of an IBM Product does not require a license

If there is a backup of a particular IBM product on a server it does not require a license.  It is important that you can demonstrate that the server is not “doing work” as defined by IBM.  For example there are not processes running associated with those products. Backup servers have been know to trigger false positives in ILMT scans and will need to be excluded from the ILMT audit snapshot report.

What’s the license impact for testing DR?

IBM allows up to four tests a year lasting up to 72 hours each.  These tests are not to include any productive work, program testing, maintenance, or development.After DR testing you will need to update your ILMT to exclude the servers that were temporarily brought on line.  A note should be added explaining that these servers are backups

How long can I run the standby server in a disaster

The IBM policy suggests a maximum of 3 weeks. Realistically it can be longer but you should get the approval (in writing) from your IBM account manager. Once the disaster has been resolved and the production systems restored you will need to update your ILMT to exclude the servers that were temporarily brought on line.  A note should be added explaining that these servers are backups.

How to reduce your IBM license costs using IBM Standby license rules

Steps to reducing your IBM license using standby rules are as follows:

  • Get a list of all servers from your DevOps team that they consider standby. It should include the server for which it is a DR for and the business owner.
  • Ask them to confirm which servers are warm and cold standby’s based on the rules described above. The naming convention of a server can be used as a guide but should not be relied upon.
  • Take a”before” snap shot of the All Metrics Report in ILMT
  • Go into ILMT and add a note to each server record clearly indicating it’s a DR server. Add as much detail as possible.
  • In ILMT exclude each server in Software Classification.
  • Check the All Metrics report and note any changes in demand
  • For each of the IBM products that have done down in license demand calculate the saving.

Take a bow, you probably just saved your company a lot of money in either new licenses that no longer need to buy or in IBM S&S that can be cancelled.


Taking advantage of the IBM license rules for standby servers is a quick and easy way to reduce license costs. With a little investigation and some changes to the way information is reported in ILMT you can reduce license costs and compliance risks.

Would you like the help of an IBM license expert? Contact me here to arrange a call.


Hot/Warm/Cold Backup Solution Definitions and Policy for Disaster Recovery Testing Flexera Post on IBM Licensing for Cold, Warm and Hot Standby  HCL (BigFix) Note on excluding a product in ILMT