Environment

• YugabyteDB v2024.2 and later versions

Issue 

Some YugabyteDB operations that create new tablet replicas such as database restores or DDL operations, fail with an error indicating that the creation of new tablet replicas would exceed the system's safe maximum limit.

The requested number of tablet replicas (X) would cause the total running tablet replica count (Y) to exceed the safe system maximum (Z)

This occurs when the additional tablets required by the operation would push the cluster above the configured tablet replica safety threshold.

Cause

In YugabyteDB v2024.2 or later version, the master gflag enforce_tablet_replica_limits is enabled by default. This feature enforces a maximum number of tablet replicas that can be created, based on available system resources (CPU cores, RAM, or both). Refer document - Tablet limits.

The flag blocks any operation that would create more replicas than the safe limit and returns an error instead.

The purpose of this safeguard is to prevent resource exhaustion and ensure stable performance when a large number of tablets are hosted on a node.
 

Resolution

1. To bypass this safety check and allow the operation to complete, you can disable the enforce_tablet_replica_limits GFlag on all masters and do a rolling restart (YBA UI -> Universe-> Edit Flags -> Add flags -> Add to Master).

          --enforce_tablet_replica_limits=false

   Note: Disabling the limit removes safeguards and may result in excessive replicas, leading to resource saturation. Use this only as a short-term workaround.

2.  For long term fix, keep enforce_tablet_replica_limits=true and scale the cluster so it stays within safe thresholds. This can mean adding more T-Server nodes, increasing CPU/RAM on existing nodes and reducing the number of tablets per table.

Related Documents :

• Tablet-limits
• Enforce-tablet-replica-limits

Reference number : SUPPORT-645