overflow/README.md

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# Geode Overflow Example

This examples demonstrates how to use Geode's Overflow to disk.

In this example, a server hosts a partitioned region that stores strings. 
The example shows entry values being overflowed to disk and removed from memory.

This example assumes that Geode is installed.

## Set up the region
1. Set directory ```geode-examples/overflow``` to be the
current working directory.
Each step in this example specifies paths relative to that directory.

2. Run a script that starts a locator and two servers. The script
then creates the ```example-region``` region and puts 4 entries.

        $ gfsh run --file=scripts/start.gfsh
        
Note that both the region size and `totalEntriesOnlyOnDisk` are 0 before we put any entries.

3. Shut down the cluster

        $ gfsh run --file=scripts/stop.gfsh
        
4. In the output of the second `show metrics --region=example-region` command, notice the line
 
`diskstore | totalEntriesOnlyOnDisk       | 2`

This shows that 2 values have been overflowed to disk and are no longer in memory.
Notice that the size from the second `describe region --name=example-region`
is still 4 

`Region   | size                   | 4`

Because all the keys remain in memory.
The entries are still accessible.