To install a GhostDB Cache Node on a server you want to act as a cache for your application, you must first obtain a copy of the GhostDB Cache Node binary.
You can also compile from source. To do this run the following:
> go build
GhostDB uses port 7991 so be sure to allow communication on that port for any servers GhostDB Cache Node is running on. Once obtained, you must create a configuration file for your cache in the same directory as the cache binary.
The configuration file is a json file and must be called “ghost_conf.json”.
There are multiple configuration options available to you. To start you must specify the keyspace size of the cache. This is the maximum number of key/value pairs you want to allow your cache to store. In the configuration file you set this value as follows:
“keyspaceSize”: 65536
If this value is not specified, the default is the same as the above.
The next configuration option you have available to you is the default time-to-live for key/value pairs. This is the number of seconds a key/value pair is considered “not-stale”. If, when using the SDK and you do not set a time-to-live on a key/value pair when storing, the default will be set to “-1”. This means the item does not expire. Otherwise, the value you provide will override the value in the configuration file. You set this value as follows in the configuration: “defaultTTL”: -1 The next configuration option is the crawler interval configuration. This is an integer value that represents how often the cache crawlers should run. The cache crawlers are concurrent crawlers that remove expired items from the cache. By default this is set to 300 seconds (5 minutes). This is set as follows in the cache:
“crawlerInterval”: 300
The next configuration option is the snitch metric interval configuration. This is an integer value that represents how often the snitch metrics sub-system should log system metrics in seconds. This is set to 300 by default (5 minutes). This is set as follows in the cache:
“snitchMetricInterval”: 300
The next configuration option is the watchdog metric interval configuration. This is an integer value that represents how often the watchdog metrics system should log application metrics in seconds. This is set to 300 by default (5 minutes). This is set as follows in the configuration file:
“watchdogMetricInterval”: 300
The next configuration option enables snapshotting within the cache. This is enabled by default and is set in the configuration file as follows:
“snapshotEnabled”: true
The next configuration option determines how often snapshotting should occur in seconds. By default this is 3600 seconds (1 hour). This is set as follows in the configuration file:
“snapshotInterval”: 3600
The next configuration option determines if your snapshots should be encrypted. This is set to true by default and is set in the configuration file as follows:
“enableEncryption”: true
In order to enable encryption you must also supply a passphrase for encrypting and decrypting the snapshots. This is set to “SUPPLY_ME” by default and should be updated. It is set as follows in the configuration:
“passphrase”: “SUPPLY_ME”
The next option available to you determines if append-only-file persistence should be used. By default this is set to false. This is set in the configuration file as follows:
“persistenceAOF”: false
The next configuration option available determines the maximum byte size of the append-only-file can grow to before it is rotated. By default this is set to 5000000 (5MB). This is set in the configuration as follows:
“aofMaxByteSize”: 5000000
If both snapshots and append-only-file are enabled in the cache, snapshots will take precedence over append-only-file. All snapshots are also compressed using gzip. This is not a configurable option. These are all the configuration options available. Below is an example of a complete configuration file:
{
"keyspaceSize": 65536,
"snitchMetricInterval": 300,
"watchdogMetricInterval": 300,
"defaultTTL": -1,
"crawlerInterval": 300,
"snapshotInterval": 3600,
"snapshotEnabled": true,
"persistenceAOF": false,
"aofMaxByteSize": 50000000,
"entryTimestamp": true,
"enableEncryption": true,
"passphrase": "SUPPLY_ME"
}