How do I modify the storage capacity of my Storage Gateway?

Resolution

Note: The following resolution applies only to Volume Gateway and Tape Gateway. To manage an Amazon FSx File Gateway or an Amazon S3 File Gateway, see Maintaining your gateway.

To modify the storage capacity on your gateway, you can add, allocate, or remove cache disks.

Remove or decrease the storage capacity

Don't remove disks that are allocated as cache disks for an existing gateway. This can break your gateway's functionality. You can't decrease the size of a cache disk after it's allocated to an existing gateway. Instead, create a new gateway with the cache space that you need. Then, migrate your data to the new gateway. Use the Storage Gateway Console to migrate data on Volume Gateway. Use the Virtual Tape Library (VTL) interface to migrate data on Tape Gateway.

For disks that are allocated as upload buffer for an existing gateway, you must first shut down the gateway before you remove the disk. Be sure to follow the steps for shutting down a gateway. If you directly shut down the instance, it can prevent access to your gateway.

After the gateway is shut down, decrease the disk size or remove it. Then, allocate a new disk with the reduced upload buffer size.

Note: When you decrease disk size or remove disks, your gateway must still have at least one buffer disk with a minimum of 150 GB.

Increase the storage capacity

Don't expand disks that you previously allocated as upload buffer or cache storage for your gateway. To increase the storage capacity of your gateway, add new disks to the gateway.

Before you add more storage to your gateway, review the required capacity for your use case:

• Upload buffer: It's a best practice to allocate at least 150 GiB of upload buffer. Use the following formula to determine the size that you need to allocate:
  (Application throughput (MB/s) - Network throughput to AWS (MB/s) * Compression factor) * Duration of writes (s) = Upload buffer (MB)
  Note: 1 GiB equals 1073.741824 MB. Even if this formula returns less than 150 GiB for your use case, it's still a best practice to allocate at least 150 GiB.
• Cache storage: For Tape and Volume Gateways, it's a best practice to allocate cache storage that's at least 1.1 times the upload buffer size. Because file gateways don't have an upload buffer in their architecture, it's a best practice to allocate at least 150 GiB of cache storage.

After you determine the storage capacity for your use case, use the Storage Gateway console to allocate the appropriate local disk capacity.

Note: To optimize your cache or upload buffer storage performance, it's a best practice to allocate the new disk with the same performance characters. For example, same RPM for mechanic desks, same disk type and raid types.