Replicating non-replicated data

Non-replicated data in a replicated file system refers to data that were added when either none or only one redundancy group exists. New data added to a replicated file system with redundancy groups 1 and 2 fully setup are replicated automatically.

Before you begin

To perform this task, you must be a user in the SYSADM, SYSCTL, or SYSMAINT group.

About this task

This task explains the steps to trigger the replication of non-replicated data in a file system. This is commonly used when you convert an existing pureScale® cluster with no replication to a cluster with replication enabled. The existing non-replicated file systems such as instance shared file system must be converted to replicated first. This puts all existing disks in each file system into redundancy group 1. This is typically followed by adding disks to redundancy group 2 and file system tiebreaker group to complete the disk setup. The last step is to trigger the actual replication of existing data. Replication of data can be I/O intensive and the duration depends on the size of data. Therefore, it is recommended to run them at off-peak usage hours.

Procedure

Run the following command for each file system to replicate data across redundancy groups:

db2cluster -cfs -replicate -filesystem <fs name>

Depending on the data placement on each disk for each file system after the previous step, IBM Spectrum Scale might mark the file system as unbalanced if a rebalance action is recommended. Db2® captures this warning from IBM Spectrum Scale and raises an alert that can be queried through the db2instance -list command. For more information, see Rebalancing a replicated file system.