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EAR is designed to provide support for those systems where High Availability (HA) of services/data is a must.
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Currently, just the [EAR Database Manager](Architecture#ear-database-manager) and the [EAR Database](EAR-Database) components offer HA support.
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The latter can be replaced by industry software like [Galera Cluster](https://galeracluster.com/).
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# EAR Database Manager HA
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Database daemons can be configured and deployed in pairs following a *server*/*mirror* schema.
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Buffering before reporting to the Database is the main duty of this Daemon, so having a mirror ensures no data lose in the case the service stops or the node where it is being running fails unexpectedly.
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Both services buffer data, but just the server inserts it to the Database.
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If it fails, the mirror starts insertion process.
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You can read how to configure two EAR Database Managers on the Configuration Guide's [Island description](Configuration#island-description) section.
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# EAR Database HA
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If the EAR Database is not deplyed on a HA system, you can manually configure EAR to report data on two databases.
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Just three actions must be performed:
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- Create two databases on two different servers. You have two ways:
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1. Use *edb_create* command.
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2. Use `edb_create -o` and redirect the output to a file. You will have the SQL query set saved to be executed directly in the DB server (mysql). \*
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- Specify **DBSECIP** field in the `ear.conf` (and propagate changes).
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- Restart Database Manager daemons.
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- Only supported in mysql.
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\* You must add a semi-colon (*;*) at the end of each line. |
