# How Salesforce migrated 200,000 Machines from CentOS 7 to RHEL 9
*Using automation for zero downtime, stronger security & faster parallel upgrades, Salesforce successfully migrated 200,000 machines from CentOS 7 to RHEL 9*
By [Rohit Lakhotia](https://scaleengineer.com/authors/rohit-lakhotia)
Published: 2025-09-22
Canonical: https://scaleengineer.com/blog/sending-email-how-salesforce-migrated-200-000-machines-from-centos-7-to-rhel-9
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