In a BigFix Distributed Server Architecture (DSA), the upgrade process must be performed sequentially to maintain database integrity and ensure successful replication. The primary server acts as the master database source. Therefore, it must be upgraded first to update the core components and database schema to the new version. After the primary server has been successfully upgraded and its services are running, the secondary (replica) servers can then be upgraded to the same version. This specific order prevents replication failures that would occur if a secondary server with a newer schema attempted to replicate with an older primary server.

A. Upgrading secondary servers first would cause a version mismatch, breaking database replication because the older primary server cannot process a newer database schema.

B. Upgrading all servers simultaneously is not a supported or recommended procedure; it introduces a high risk of race conditions, replication failure, and data corruption.

D. This sequence is incorrect. The primary server must be upgraded before any action is taken on the secondary servers, including using a Fixlet.

1. HCL BigFix Installation Guide Version 10.0. In the section "Upgrading a DSA environment

" the procedure explicitly states: "To upgrade a DSA environment

you must first upgrade the primary BigFix server and then upgrade the secondary BigFix servers." This is followed by the step-by-step process which begins with upgrading the primary server. (Reference: Chapter 4: Upgrading

Section: Upgrading a DSA environment).

2. HCL BigFix Documentation Portal. The article on "Server Upgrade" for DSA environments consistently outlines the procedure of upgrading the primary server before any secondary servers. The documented steps are: 1. Stop services on all servers. 2. Back up databases. 3. Upgrade the primary BigFix server. 4. Start services on the primary. 5. Upgrade the secondary BigFix servers. 6. Start services on the secondaries. (Reference: HCL BigFix Platform 10.0 > Installing > Upgrading > Upgrading a DSA environment).