Description

INFINIDAT discovered multiple stability issues with the InfiniBox NAS asynchronous replication. While these issues require a specific low probability chain of events, the high impact led INFINIADT to impose a set of limitations on NAS asynchronous replication as described below.

Pre-4.0.5 NAS Async Replication

Pre-4.0.5 NAS Async Replication should not be used at all, and if already used should be upgraded to 4.0.5 ASAP.

4.0.5 NAS Async Replication Limitations

NAS Async Replication change-role operation may cause a data inconsistency at the source side (that may also replicate to the target side).

The issue affects 4.0.0;4.0.1;4.0.5 versions, as a result in 4.0.5 change role operation is disabled in the GUI & CLI for non-infinidat user roles. 

NAS Async change-role through API is still possible, but should not be used, as its usage exposes the relevant filesystem to data inconsistency.

VMWare SRA 4.0 should not be used for NAS datastores (as it accesses the API directly).

Note that VMWare SRA 4.0 for SAN is not affected by this issue and can be safely used.

Workaround

Change-role through deleting the replica and creating a new one with reversed roles. This process will perform a full initial sync.

1) Delete NAS Async Replica

2) Start using (mount) filesystem at (what used to be) target system

3) Create NAS Async replica from the new source. This will require full initial sync.

Fix & Resolution timeline

The resolution for change-role issue in NAS Async will be included in the next maintenance release.

INFINIDAT recommends NAS Async production workloads to use the next maintenance release (4.0.10).

Relevant issues

INFINIBOX-32454 - ( )