# Understanding Storage Gateway Resources and Resource IDs
Understanding Resources and Resource IDs

In Storage Gateway, the primary resource is a *gateway* but other resource types include: *volume*, * virtual tape*, *iSCSI target*, and *vtl device*. These are referred to as *subresources* and they don't exist unless they are associated with a gateway.

These resources and subresources have unique Amazon Resource Names (ARNs) associated with them as shown in the following table.


| Resource Type | ARN Format | 
| --- | --- | 
|  Gateway ARN  |  `arn:aws:storagegateway:region:account-id:gateway/gateway-id`  | 
| Tape ARN |  `arn:aws:storagegateway:region:account-id:tape/tapebarcode`  | 
| Target ARN ( iSCSI target) |  `arn:aws:storagegateway:region:account-id:gateway/gateway-id/target/iSCSItarget`  | 
|  VTL Device ARN  |  `arn:aws:storagegateway:region:account-id:gateway/gateway-id/device/vtldevice`  | 

Storage Gateway also supports the use of EC2 instances and EBS volumes and snapshots. These resources are Amazon EC2 resources that are used in Storage Gateway.

## Working with Resource IDs
Working with Resource IDs

When you create a resource, Storage Gateway assigns the resource a unique resource ID. This resource ID is part of the resource ARN. A resource ID takes the form of a resource identifier, followed by a hyphen, and a unique combination of eight letters and numbers. For example, a gateway ID is of the form `sgw-12A3456B` where `sgw` is the resource identifier for gateways.

For virtual tapes, you can prepend a up to a four character prefix to the barcode ID to help you organize your tapes.