A Jethro instance consists an entire database, including all tables, data, indexes, and metadata. The instance is stored on a chosen type of storage, either shared (such as HDFS or EFS) or local (POSIX). An instance can be attached to a server, but can also be detached and reattached later (by the same server or another).

This chapter provides instructions for performing the following operations:

Creating an Instance

To create a new, empty instance, run the command JethroAdmin create-instance along with the following parameters:

The syntax of the basic command is:

# Basic command:
JethroAdmin create-instance < instance-name > -storage-path=<storage-path> -cache-path=<cache-path> -cache-size=<cache-size> [-Dstorage.type=POSIX]

# To create a local instance, run:
JethroAdmin create-instance demo -storage-path=/user/jethro/instances -cache-path=/mnt/jethro_local_cache -cache-size=0G -Dstorage.type=POSIX 

# To create an HDFS instance, run:
JethroAdmin create-instance demo -storage-path=/jethro/instances -cache-path=/mnt/jethro_local_cache -cache-size=80G

Attaching and Detaching an Instance

Instances can be attached/detached from a server. When using a shared storage, they can (and most probably will) be attached to multiple servers.
To attach an existing instance, run:

JethroAdmin attach-instance { instance-name } -storage-path={storage-path} -cache-path={cache-path} -cache-size=80G {-Dstorage.type=POSIX}

To detach an instance from a server, run:

JethroAdmin detach-instance { instance-name }

Deleting an Instance

To remove an instance and all its data and metadata, run:

JethroAdmin delete-instance < instance-name >