Last year Salesforce implemented a Continuous Site Switching (CSS) program which entails site switching each instance approximately once every six months for maintenance, compliance, and disaster recovery purposes.


The 2019 Continuous Site Switching Schedule through July 2019 is as follows:


  • March 2, 2019 | NA32, NA37, NA54, NA67
  • March 3, 2019 | NA40, NA47, NA51, NA63
  • March 16, 2019 | CS25, CS26, CS92, CS97
  • April 6, 2019 | CS5, CS53, CS68, CS84, CS85, CS88, CS89, CS90, CS91 CS115, CS116
  • April 20, 2019 | EU7, EU8, EU12, NA53
  • April 21, 2019 | NA46, NA72, NA76, NA88
  • June 15, 2019 | EU14, EU15, EU16, EU17, EU18, NA65, NA66, NA70
  • June 16, 2019 | NA69, NA90, NA94, NA99
  • July 6, 2019 | AP8, AP9, AP14, AP15, EU13, NA61, NA64, NA79
  • July 7, 2019 | NA49, NA57, NA59, NA87
  • July 20, 2019 | CS12, CS20, CS21, CS23, CS31, CS72, CS102, CS105, CS106, CS137



Who is impacted by this change?

All customer and partners globally will be impacted by this change in our maintenance policy.


What is the change?

Each Salesforce instance is built and maintained in two geographically separate locations. An instance is actively served from one location (the active site) with transactions replicating in near real-time to the other completely redundant location (the ready site). This infrastructure model allows us to switch the location of the active site for maintenance, compliance, and disaster recovery purposes, which is referred to as a site switch. As part of our Continuous Site Switching program, Salesforce switches the active and ready instance locations approximately once every 6 months.


Why is this change happening?

Continuous site switching allows us to continuously improve our operations and infrastructure in order to provide you with the high availability of our services you’ve come to expect. In addition, continuous site switching satisfies the internal compliance requirement of many of our customers that their instances are capable of being served from either geographic location throughout the year.


When will these changes take place?

With the Continuous Site Switching program, each instance will undergo a planned site switch approximately once every six months. These planned site switches will only occur during standard system maintenance windows, which are scheduled the first and third weekends of every calendar month and are unique to each instance.


What's the impact to customers and partners?

During a site switch, impacted customers and partners can access their org in read-only mode. At the beginning of the program, site switch maintenance windows may last upwards of 90 minutes. As we improve our operational processes through practice and iteration, our goal is to reduce this window over time.


What action do I need to take?

  1. If you already follow our infrastructure best practices by not restricting access to Salesforce IP ranges and setting your DNS timeout value to 5 minutes (default setting), a site switch should be seamless to your users.
  2. If you are restricting access to certain IP ranges or data centers, update your network settings to include the complete list of Salesforce IP ranges from the What are the Salesforce IP Addresses to whitelist? article in order to avoid any unintended service disruptions following a site switch.
  3. If you control your DNS timeout values set, then you may need to refresh your DNS cache and restart any integrations following the maintenance.

Where can I go for more information?

The Continuous Site Switching schedule is posted and maintained on our Trust maintenance calendar. To determine if a specific instance is on the schedule, click on the instance at or visit<INSTANCE> (example: and review the maintenance calendar for that instance.


We recommend that you and your customers subscribe to Trust Notifications to stay informed of maintenances, including site switches, that are scheduled and to receive updates during the maintenance. More information on Trust Notifications can be found here.


For more information on what happens during a site switch and how to make sure your org is best prepared, see our Site Switching Overview article.