How is Volume Gateway different to File Gateway? Is it just volume of data? I'm having a hard time understanding about iSCSI block storage. What are some examples of how volume gateway is being used?
CodePudding user response：
You can think of File Gateway like a "share folder" that sits in AWS S3. Let say you have an application that generates PDF files into that shared folder, it will eventually it will end up in the AWS S3 bucket.
Volume Gateway on the other hand is like a disk volume (e.g. C: drive) that connects to the operating system, it uses iSCSI protocol, your operating system would treat it like a hard disk that is connected to, but it's located somewhere remotely.
Volume Gateway can operate in 2 modes
- Cached mode - your primary data is written to S3 while retaining your frequently accessed data locally in a cache for low-latency access.
- Stored mode - your primary data is stored locally and your entire dataset is available for low-latency access while asynchronously backed up to AWS.
Here's a video explaining them
CodePudding user response：
In short:
Volume Gateway can operate in 2 modes:
- Stored Mode:
- Used for creating backups of local drives
- Data is uploaded into S3 as EBS snapshots, so can be used as EBS volumes for EC2
- The full copy of the data is stored locally, uploads happen in async mode
- Cached Mode:
- Can be used for datacenter extension, meaning that a small amount of data is stored locally (cached) while everything else is stored in S3
- Although data is stored in S3, this wont be visible in AWS console
In both cases, data is stored raw block state. Volumes are presented to on-prem devices over iSCSI.
File Gateway in the other hand:
- Offers mount point for on-prem devices (and EC2) to which we can connect via NFS or SMB
- Files are visible from S3 AWS console, File Gateway essentially presents a bucket as a network drive
- Multiple entities can connect to a mount point and share files, although there is no object locking