[fedora-arm] ARM Build System Upgrading - Downtime Scheduled

At a Seneca team meeting this afternoon, we planned out the upgrade process for the ARM build system. There will be several pre-upgrade operations tomorrow and Monday, with downtime scheduled to begin at 9 am EST / 1400 UTC on Tuesday, December 13. The upgrades should be completed within 48 hours (by 1400 UTC Thursday, December 15). Builders will be disabled several hours before the start of scheduled downtime to prevent new builds from starting. The upgrades involve: - Doubling the number of x86_64 servers, from two to four. - Moving /mnt/koji to SSDs (supporting up to 117 KIOPS read and 69 KIOPS write). - Moving the Koji db to a separate server (using the SSDs we migrated to yesterday). - Switching to a 4-drive RAID-0 configuration for builder scratch space (from a 2-drive JBOD). - Physically re-racking and re-cabling the 60-70 machines for better airflow and access. - Adjusting backups, scripts, network configuration, and DNS to support the new configuration. -- Chris