In my other post, I discussed the differences between AWS file gateway and volume gateway. In this post, I will discuss the differences between the two gateway modes that volume gateway offers; cached and stored. Both modes provides iSCSI interface access to Amazon S3 storage using AWS Storage Gateway. However, the following are some differences between them to be aware of :
| Cached Volume Gateway | Stored Volume Gateway |
| Cached volume gateway provides low latency access to the data that is stored in its local cache disk. Cached Gateway storage volumes uses Amazon S3 as back-end storage. | Stored volume gateway provides low latency access to all of your dataset. You use your local on-premises SAN/DAS storage and assign it to the stored gateway VM. Then, use that storage to create storage volumes. |
| You can deploy on Amazon EC2 host platform in addition to other on-premises hypervisor platforms. | You cannot deploy on Amazon EC2 host platform. You can only deploy on on-premises hypervisor platforms. |
| You need at least two local disks, one for cache storage and one for upload buffer. | You need local disks for the upload buffer and your storage volumes. You don’t assign cache storage. |
| No default snapshot schedule for volumes, but you can configure scheduled snapshot using AWS Backup or AWS Storage Gateway. | Default snapshot schedule of one in every 24 hours. You cannot disable this, as data is stored on local disks and backups are taken to Amazon S3. |
| Volumes can go to pass through/bootstrapping status when there are issues with upload buffer space utilization. | Volumes can go to pass through/bootstrapping/restoring pass through statuses. Pass through and bootstrapping can happen when you create/expand a storage volume preserving the existing data. |
| Maximum size of a volume is 32 TiB. | Maximum size of a volume is 16 TiB. |
| Total size of all volumes for a gateway is 1,024 TiB. | Total size of all volumes for a gateway is 512 TiB. |
References:
https://docs.aws.amazon.com/storagegateway/latest/vgw/WhatIsStorageGateway.html