An ArcGIS Enterprise deployment is composed of the following:
- An ArcGIS Enterprise portal*
- One or more ArcGIS Server sites*
- Data stores (including registered databases, files in registered folders, and an ArcGIS Data Store relational data store*)
- Web Adaptors* or at least one load balancer
- A domain name system (optional)
- A file server for the ArcGIS Server configuration store
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.
High-availability configurations for ArcGIS Enterprise are designed for use within a single data center or equivalent, such as a cloud region, to protect against individual components becoming unavailable and causing system downtime. Highly available ArcGIS Enterprise components are not designed to be deployed across multiple data centers. In a highly available configuration, if any single machine running an ArcGIS Enterprise component partially or completely fails, users can still access the ArcGIS Enterprise deployment. Examples of failure include hard disk failure, network card failure, or operating system failure.
To protect against multiple failures or the unavailability of the entire deployment, combine disaster recovery techniques with high availability.
If one machine fails, the overall capacity of the system is reduced. Therefore, you should build in extra capacity to each machine in your ArcGIS Enterprise deployment so the remaining machines can handle the load if a machine fails.
It is also important to monitor your deployment so you can correct the failure as soon as possible. If a second failure occurs before you correct the first, your ArcGIS Enterprise deployment could become partially or completely unavailable.
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 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. You should also configure the load balancer to perform a health check of the ArcGIS Server machines.
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 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 Server 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 managed data stores
ArcGIS Data Store holds data for several types of hosted web services that run on your portal's hosting server. ArcGIS Data Store provides failover functionality that allows these hosted services to remain available even when a data store machine fails.
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 site you will use as 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.
ArcGIS Data Store automatically replicates hosted feature layer data from the primary data store to the standby; therefore, the data exists in two places. The GIS Server always communicates with the active (primary) data store.
Once you add a standby relational data store, the standby becomes 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.
For highly available hosted scene layer caches, install ArcGIS Data Store on two or more machines and create a tile cache data store on each machine. Configure each tile cache data store with the GIS Server you will use as your portal's hosting server. When portal members publish hosted scene layers, ArcGIS Data Store ensures the caches are stored on at least two machines in the tile cache data store.
For highly available archived observation data used with ArcGIS GeoEvent Server, location tracking services, 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 dataset 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 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.
Once you configure a highly available portal, the primary portal replicates items to the standby portal. If the primary machine becomes unavailable, the standby is promoted to primary with all of the current items. If you stop the Portal for ArcGIS service or the primary machine becomes unavailable (for example, the hard drive fails), the portal will failover to the standby. Once the machine returns from the failure or you restart the Portal for ArcGIS service, that machine will rejoin the portal as the standby machine. Configure the load balancer for the WebContextURL and the privatePortalURL to check the health of the portal machines.
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.