Use the Overlay Local Filesystem

This topic describes how to configure the local filesystem as the block storage backend provider for the Storage Controller (SC).

Prerequisites

Successful completion of all the install sections prior to this section.
The SC must be installed, registered, and running.
The local filesystem /var/lib/eucalyptus/volumes must have enough space to hold volumes and snapshots created in the cloud.
You must execute the steps below as a Eucalyptus administrator.

In this configuration the SC itself hosts the volume and snapshots for EBS and stores them as files on the local filesystem. It uses standard Linux iSCSI tools to serve the volumes to instances running on NCs.

To configure overlay block storage for the zone, run the following commands on the CLC

Configure the SC to use the local filesystem for EBS.
```
euctl ZONE.storage.blockstoragemanager=overlay 
```
The output of the command should be similar to:
```
one.storage.blockstoragemanager=overlay
```
Verify that the property value is now: 'overlay'
```
euctl ZONE.storage.blockstoragemanager
```
Verify that the SC is listed; note that it may be in the broken state:
```
euserv-describe-services --filter service-type=storage
```

Your local filesystem (overlay) backend is now ready to use with Eucalyptus.