This section contains all you need to know to operate databases hosted on Redis Enterprise Software.

    Causal Consistency in a Conflict-free Replicated Database (CRDB)

    When enabling Causal Consistency in CRDBs, the order of operations on a specific key will be maintained across all CRDB instances. For instance, if operations A and B were applied on the same key, and B was performed after the effect of A was observed by the CRDB Instance that initiated B, then all CRDB instances would observe the effect of A before observing the effect of B. This way, any causal relationship between operations on the same key is also observed and maintained by every replica.

    Create a Geo-Replicated Conflict-free Replicated Database (CRDB)

    CRDBs span multiple Redis Enterprise Software (RS) clusters. Overview of the steps to create a CRDB: Create a service account on each cluster as an admin Confirm network is setup Connect to one of your clusters and configure a new CRDB Test writing to one cluster Test reading from a different cluster Prerequisites Two or more Redis Enterprise Software clusters running version 5.0, each with minimum of two nodes Networking and cluster FQDN name resolution between all clusters Confirm that a network time service listener (e.

    Creating a Redis Enterprise Software (RS) database

    You can create as many databases as you wish in the cluster, so long as you do not exceed the available memory or the number of shards you purchased with your subscription. There are two types of Redis databases that can be created in RS. Traditional Redis databases that are sharded and distributed across a single RS cluster. The detailed instructions are covered below. Conflict-Free Replicated Database (CRDB) which is used to create a Geo-Distributed Active-Active Redis database.

    Database alerting

    In the Alerts section of the Redis Enterprise Software database page, you can designate which database events will trigger alert notifications. For instructions on configuring alerts at the cluster level, refer to Managing cluster alerts. Some alerts can only be turned on or off, such as Periodic backup failed. Some alerts require setting a threshold, such as Dataset size has reached a certain percentage of its limit. Configured alerts appear in the database Status field, in the Log page, and can also be sent by email.

    Database memory limits in Redis Enterprise Software

    When you set a database's memory limit, you define the maximum size the database can reach in the cluster, across all database replicas and shards, including: Slave shards (if database replication is enabled) Database shards (if database clustering is enabled) If the total size of the database in the cluster reaches the memory limit, the data eviction policy that was defined for the database is applied. The following examples show how different database configurations affect the total database size.

    Delete a Database

    To delete a database in Redis Enterprise Software (RS): Click the relevant database row in the Databases page. The selected database page appears. Select the Configuration tab. Click Delete at the bottom of the page. Confirm the deletion.

    Deleting a Conflict-free Replicated Database (CRDB)

    Deleting a CRDB is a nearly identical procedure to standard Redis databases in Redis Enterprise Software, but with a critical distinction. Since CRDBs span multiple Participating Clusters, there is more extensive administrative work being done on the clusters on your behalf. When you click the button on the configuration tab to delete a CRDB, this action is an immediate, non-reversible, and has no rollback. The cluster deletes all member databases from all Participating Clusters on your behalf.

    Eviction policies

    The eviction policy designates a data eviction method for Redis Enterprise Software (RS) to use when the database size reaches its limit. You can select any of the following: Policy Description  noeviction Returns an error if the memory limit has been reached when trying to insert more data  allkeys-lru Evicts the least recently used keys out of all keys  allkeys-random Randomly evicts keys out of all keys  volatile-lru Evicts the least recently used keys out of all keys with an "expire" field set  volatile-ttl Evicts the shortest time-to-live and least recently used keys out of all keys with an "expire" field set.

    Exporting Data from Redis Enterprise

    Using the Export option, you can back up a database at any time to an FTP server, Amazon S3, or OpenStack Object Storage ("Swift"). Other cloud storage options, such as Azure Geo-Redundant Storage, SoftLayer Object Storage, and Google Cloud Storage will be added in a future release. You cannot back up to the local machine. To perform a database export: Click the relevant database row in the Databases page.

    Importing Data into Redis Enterprise

    You can import data into a Redis Enterprise Software database from an HTTP location, FTP server, Amazon S3, or OpenStack Object Storage ("Swift"). You can either import from a single file, or from multiple files in case you are importing from a backup of a sharded database. For additional details, refer to the Backup of a sharded database section in Database backup. Note: Importing data via this method will erase all existing content in the database.

    Importing Data into your CRDB

    When importing data into a CRDB, there are two options: Perform a flushall to the database, thus deleting all data. Then import the data into the CRDB. Import data but merge it into the existing or add new data from the import file. When using option #2, there are special considerations to be aware of. Unlike a traditional Redis database, CRDBs have a numeric counter data type and thus require special ways to increment.

    Metrics

    On the Database > Metrics page you can view detailed real-time graphs of various database metrics, as well as shard-related metrics. Database metrics You can choose which metrics are shown in each of the two detailed graphs at the top of the page, as follows: Below the top two graphs there is a group of smaller graphs that display all available metrics, such as CPU utilization and operations per second.

    Periodic Backups

    You can back up your dataset to an FTP server, Amazon S3, or OpenStack Object Storage ("Swift"), periodically, or ad-hoc. You cannot back up to the local machine. Other cloud storage options, such as Azure Geo-Redundant Storage, SoftLayer Object Storage and Google Cloud Storage will be added in a future release. The backup process creates compressed (.gz) RDB files. Note: It is your responsibility to manage the backup location; Redis Enterprise Software does not delete old backups or monitor the amount of space left in the folder.

    Updating database configuration

    You can change the configuration of a Redis Enterprise Software database at any time. To edit the configuration of a database: Click the relevant database row on the Databases page. The selected database page appears. Select the Configuration tab. Click Edit at the bottom of the page. The database settings appear. You can edit any of the configurable parameters. For explanation, refer to Creating a new database. Click Update.  Updating CRDB configuration