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IBM Flash system Non-Disruptive Upgrade (NDU) using Nondisruptive volume migration between systems.

By Rajsekhar Bharali posted Sun March 19, 2023 02:49 AM


IBM Flash system Non-Disruptive Upgrade (NDU) using Nondisruptive volume migration between systems.

With ever increasing demand for performance and capacity at times customers are required to deploy newer versions of Flash System Hardware to keep up with the demand.

There are native and legacy ways to upgrade the system where it takes weeks to upgrade the whole system and the whole process spans for weeks. Such process may not provide 100 % availability of data and may require application downtime.


With IBM Storage Flash system, you can perform NDU by non-disruptively migrating the volume from older System to the New state of the art IBM Storage Flash System.

Non disruptive volume migration uses the existing Remote Copy Metro Mirror link. However, it does not require any Remote Mirroring license before you can configure a remote-copy relationship that is used for migration.

Upgrade Scenario

Let’s say a customer has a pair of SV1 nodes which is getting decommissioned and out of warranty in coming time. Refer figure 1.

Figure 1

The customer decides to upgrade the Systems to a state-of-the-art IBM Storage FS9500.

The customer can non disruptively migrate all volumes from IBM San Volume controller SV1 to enclosure-based IBM flash system without any application downtime.

Before you can use non-disruptive system migration function, ensure that the following prerequisites are met:

  • Ensure that both systems are running 8.4.2 or later.
  • Create either a Fibre Channel or IP partnership between the two systems that you want to migrate volumes between. The maximum supported round-trip time (RTT) between the two systems is 3 milliseconds. Ensure that the partnership has sufficient bandwidth to support the write throughput for all the volume you are migrating. 
  • Ensure any hosts that are mapped to volumes that you are migrating are correctly zoned to both systems. Hosts must appear in an online state on both systems.

Using Flash System GUI Customer performs the below action to complete the whole NDU procedures: 

  1. On the source system, select Volumes > Volumes. On the Volumes page, identify and record of the volume name and capacity of all the volume to be migrated.
  2. On the target system create volume with identical size and tier properties.
  3. On both the systems go to Copy Services > Partnerships and Remote copy > Create partnership to create IBM Fibre channel or IP relationship between the source and the target system.
  4. On the source system select Copy Services > Remote Copy to create Non-disruptive System Migration Independent Relationship. This sync the UUID of target volume to the source volume. Figure2
  5. Once the relationship is in consistent synchronized state, i.e., both the volumes are identical, create host mappings to the target volume on the target cluster. The volume rescan on the host should be triggered manually to discover the new paths as ghosts or standby paths.Figure 3
  6. Select Copy Services Remote Copy > Independent Relationship. Right-click the migration relationship and select Switch Direction. This action reverses the copy direction of the relationship and switches the active and standby paths, which result in all host I/O being directed to the target volumes. Verify that all previously active paths are now reporting standby (or ghost). Validate that all hosts are using the target volume for I/O and verify that no issues exist.Figure 4 
  7. On the original source system that was used in the migration, select the Hosts > Hosts. Right-click the hosts and select Unmap Volumes. The host is now running IO on the volumes presented from FS 9500Figure 5
  8. Voilà Non-Disruptive Upgrade from IBM SVC SV1 controller to IBM Flash System 9500 using volume migration is now complete.