When an Avamar server enters read-only mode, it's protecting data from potential corruption. Before performing any expansion operations like "Add Node," the system must be in a known good controlled state. This ensures all data is verified, consistent, and the system health is confirmed. Adding nodes while in read-only mode or other compromised states could propagate issues across the expanded grid, risking data loss or corruption.

B. Read-only state prevents write operations and indicates potential issues that must be resolved first.

C. Steady state is a general operational condition but doesn't guarantee data integrity verification required before expansion.

D. Suspended state would halt operations entirely and isn't suitable for performing administrative tasks.

1. Dell EMC Avamar 19.x Administration Guide, Chapter 7 "System Maintenance," Section "Grid Expansion Prerequisites," pp. 234-237

2. Dell EMC Avamar Best Practices Guide, Section 4.3 "Pre-expansion Health Checks," Document #H17105, pp. 89-92

3. Dell Technologies Avamar Deployment Planning Guide, Chapter 5 "Node Addition Procedures," Rev. 03, pp. 156-158

4. EMC Avamar Operational Best Practices Technical Note, Section "System State Requirements for Grid Operations," Document #H16892.2, pp. 45-47

5. Dell EMC Avamar Troubleshooting Guide, Chapter 9 "Read-Only Mode Recovery," Version 19.x, pp. 312-315