changed HA to High Availability. Referenced disaster recovery

Author: Matt Duff

README.md

@@ -13,7 +13,7 @@ This repository includes backup and recovery utilities for [GitHub Enterprise][1
 - **[Using the backup and restore commands](#using-the-backup-and-restore-commands)**
 - **[Scheduling backups](#scheduling-backups)**
 - **[Backup snapshot file structure](#backup-snapshot-file-structure)**
-- **[How does backup utilities differ from an HA (High Availability) replica?](#how-does-backup-utilities-differ-from-an-ha-high-availability-replica)
+- **[How does backup utilities differ from a High Availability replica?](#how-does-backup-utilities-differ-from-an-ha-high-availability-replica)
 - **[Support](#support)**
 
 ### Features
@@ -232,14 +232,14 @@ most recent successful snapshot:
 Note: the `GHE_DATA_DIR` variable set in `backup.config` can be used to change
 the disk location where snapshots are written.
 
-### How does backup utilities differ from an HA (High Availability) replica?
-It is recommended that both backup utilities and an [HA replica](https://help.github.com/enterprise/admin/guides/installation/high-availability-cluster-configuration/) are used as part of a GitHub Enterprise deployment but they serve different roles.
+### How does backup utilities differ from a High Availability replica?
+It is recommended that both backup utilities and an [High Availability replica](https://help.github.com/enterprise/admin/guides/installation/high-availability-cluster-configuration/) are used as part of a GitHub Enterprise deployment but they serve different roles.
 
 ##### The purpose of the High Availability replica
-The HA replica is a fully redundant secondary GitHub Enterprise instance, kept in sync with the primary instance via replication of all major datastores. This active/passive cluster configuration is designed to minimize service disruption in the event of hardware failure or major network outage affecting the primary instance. Because some forms of data corruption or loss may be replicated immediately from primary to replica, it is not a replacement for the backup utilities as part of your disaster recovery plan.
+The High Availability replica is a fully redundant secondary GitHub Enterprise instance, kept in sync with the primary instance via replication of all major datastores. This active/passive cluster configuration is designed to minimize service disruption in the event of hardware failure or major network outage affecting the primary instance. Because some forms of data corruption or loss may be replicated immediately from primary to replica, it is not a replacement for the backup utilities as part of your disaster recovery plan.
 
 ##### The purpose of the backup utilities
-Backup utilities takes date-stamped snapshots of all major datastores. These snapshots are used to restore an instance to a prior state or set up a new instance without having another always-on GitHub Enterprise instance (like the HA replica).
+Backup utilities are a disaster recovery tool. This tool takes date-stamped snapshots of all major datastores. These snapshots are used to restore an instance to a prior state or set up a new instance without having another always-on GitHub Enterprise instance (like the High Availability replica).
 
 
 ### Support