An ArcGIS Enterprise deployment is comprised of the following:
- Web adaptors* and at least one load balancer
- A domain name system (optional)
- A file server for the ArcGIS GIS Server configuration store
- One or more ArcGIS GIS Server sites*
- Data stores (including registered databases, files in registered folders, an ArcGIS Data Store relational data store*)
- A portal (in on-premises deployments, this is Portal for ArcGIS*)
ArcGIS offers tools and functionality that allow you to configure high availability for those components listed with an asterisk (*). The other components require use of third-party tools and functionality to configure.
Each component manages redistribution or failover when a machine in the configuration fails or becomes inaccessible. For more information on the different components, when they should be used, and how they should communicate with one another, see Deployment scenarios for a highly available ArcGIS Enterprise.
The following sections explain high availability for each component and link to instructions to configure high availability for the ArcGIS components of an ArcGIS Enterprise deployment.
Configure a highly available ArcGIS Server site
ArcGIS Enterprise deployments contain a hosting server. This is an ArcGIS GIS Server you have dedicated to running your portal's hosted services, such as hosted feature, tile, and scene layers. You might choose to federate additional ArcGIS Server sites with your portal to allow them to share authentication and to automatically register web services as items in your portal. Or you might federate ArcGIS GeoAnalytics Server, ArcGIS GeoEvent Server, or ArcGIS Image Server sites with your portal. You can configure any of these sites to be highly available.
How you implement a highly available ArcGIS Server site depends on whether your web services reside on a single machine or are spread across multiple machines.
If your services run on one machine, configure a primary and a standby site. Also configure a load balancer to communicate with the active ArcGIS Server machine. The primary and standby sites will each have their own server directories and configuration store. These directories must be identical.
If your ArcGIS Server site is static (for example, you have published the web services you need and won't be publishing more) you can configure both the primary and standby sites to be active. In this case, the primary and standby share an output directory that you configure on a highly available file server. However, this is an unlikely scenario when your ArcGIS Server site is used with Portal for ArcGIS and most likely would not be used.
If you have multiple machines in your site, configure a load balancer to communicate with your pool of ArcGIS Server machines. This pool of machines shares server directories and a configuration store. Again, configure these directories on a highly available file server to implement a highly available ArcGIS Server.
See the following topics in the ArcGIS Server help for information on configuring a highly available single or multiple machine ArcGIS Server site:
- Single machine high availability (active-passive) deployment
- Multiple machine deployment with ArcGIS Web Adaptor
Note that when you federate a highly available ArcGIS Server site with Portal for ArcGIS, set the Administration URL to a URL that the portal can use to communicate with all servers in the site, even when one of them is unavailable, such as a load balancer URL.
Also be aware that using a load balancer URL affects the way you connect to ArcGIS Server Manager. For example, if you federate using a load balancer URL, you must connect to Manager using the load balancer; you cannot use the default ArcGIS Server Manager URL of http://gisserver.domain.com:6080/arcgis/manager or https://gisserver.domain.com:6443/arcgis/manager.
Configure highly available data stores
To have highly available hosted feature layer and hosted scene layer caches, install ArcGIS Data Store and configure primary and standby relational and tile cache data stores. Once you add a standby data store, the standby will become active if any of the following occurs:
- The primary data store stops working. ArcGIS Data Store attempts to restart the data store on the primary machine. If it cannot restart, the data store fails over to the standby.
- The primary's web app stops running and attempts to restart the web app on the primary machine. In the rare case that this does not work, the data store fails over to the standby machine.
- The primary machine is unavailable. This can happen if the computer crashes, is unplugged, or loses network connectivity. ArcGIS Data Store makes five attempts to connect to the primary machine. If a connection is not possible after five attempts, the data store fails over to the standby machine.
To have highly available archived observation data or big data feature analytics output, install ArcGIS Data Store and configure three or more spatiotemporal big data stores with your hosting server.
Use ArcGIS Data Store as the data store for your portal's hosting server and you can take advantage of the failover functionality it provides.
For highly available hosted feature layer data, install ArcGIS Data Store on two separate machines and create a relational data store on each machine. Configure each relational data store with the GIS Server you will use with your portal's hosting server. The first relational data store you configure is the primary relational data store machine; the second machine you configure is the standby data store.
For highly available hosted scene layer caches, install ArcGIS Data Store on two separate machines and create a tile cache data store on each machine. Configure each tile cache data store with the GIS Server you will use with your portal's hosting server. The first tile cache data store you configure is the primary tile cache data store machine; the second machine you configure is the standby data store.
ArcGIS Data Store automatically replicates hosted feature layer data and hosted scene layer caches from the primary data store to the standby; therefore, the data exists in two places. The GIS Server will always communicate with the active (primary) data store.
For highly available archived observation data used with ArcGIS GeoEvent Server or to make the data generated from big data feature analysis highly available, you can install ArcGIS Data Store on three or more machines and create a spatiotemporal big data store on each. Configure each data store with your portal's hosting server. A copy of each data set exists on at least two of the data store machines at any time. If one machine fails, the data store ensures that at least two of the remaining machines contain the data.
For more information and instructions, see Add a machine to your data store.
Configure a highly available portal
A highly available portal includes two Portal for ArcGIS machines accessed through a load balancer. The load balancer redirects incoming requests to the active portal machine.
The two portal machines store content in a common directory. For your portal to be highly available, you must configure this content directory on a highly available file server.
See Configure a highly available portal for more information and instructions.
Configure highly available source data
You publish data to ArcGIS Server sites from a variety of sources. If you register folders or databases with the ArcGIS Server sites in your ArcGIS Enterprise deployment, you need to store that source data in a manner or location that meets your high availability needs. For file sources in folders, store on a highly available file server. For databases, use the technology of your database management system to ensure high availability.
Combine high availability and disaster recovery
In most cases, you will implement a disaster recovery plan in addition to a highly available deployment. That way, if all the machines in your deployment are lost (such as in a natural disaster), you still have a backup of your data and services you can use to bring your deployment back online. Either maintain backups in a secure, offsite location or maintain a disconnected standby deployment in a remote location.