As defined in Wiki, A cloud storage gateway is a network appliance or server which resides at the customer premises and translates cloud storage APIs such as SOAP or REST to block-based storage protocols such as iSCSI or Fibre Channel or file-based interfaces such as NFS or CIFS. – wikipedia.org
Cloud Storage Gateway or just Cloud Gateway is a new product category. The main benefit is that it can bring cloud storage on-premise to where you work.
When it comes to pick a cloud storage gateway, there are several questions to ask before you buy one.
(1) Which form is it in?
The gateway may come in three different forms. Based on the different forms, there are different questions to ask.
- Pure software. For example, Gladinet CloudAFS or Nirvanix Cloud NAS are software, with software installation packages.
- Support Windows or Linux?
- 32-bit or 64-bit?
- Can the software be installed in VMWare?
- What is the recommended system requirements?
- Virtual Appliance. For example, Nasuni Filer, comes with VM image.
- VMWare or Xen or Hyper-V?
- Physical Appliance. Traditional NAS device vendors may have cloud storage support embedded.
All forms are OK, you will need to know to fit your existing IT infrastructure. If it comes as software, you may need to install it on a physical server or inside a VM machine. If it comes with Virtual Appliance, you will need to merge it into your existing virtual environment. If it comes with a physical NAS, you will plug it into your network.
(2) Which cloud storage does it support?
There are many different cloud storage service providers out there. You can make a check list and check them off.
One of the key differentiator in the cloud storage providers is money. If you are already using a service from a service provider, it is very likely you get a price break when do in-network transfer. So you may prefer a cloud gateway that supports a specific cloud storage provider.
For example, Gladinet supports many of the cloud storage providers and the list is growing. The overall trend is to support all of them.
You don’t need a cloud gateway that supports them all, you just need one that supports what you need now as the primary and a backup provider in case you need to switch two months down the road.
(3) How is my data stored on the cloud storage?
There are two ways to store data:
- Store at blocks level
- Store at file level
Almost all cloud storage providers provide storage at the object level, which is the common language everyone speaks. The object can represent a block or a file. If everyone stores at the file level, then you can jump from Cloud Gateway vendor A to vendor B and can still read the file back. If the gateway stores at block level, it will be vendor specific and proprietary to the vendor, you can’t get the files back since only the vendor knows how to put the blocks back into a file.
For example, Gladinet CloudAFS stores at the file level. If you save a file to Amazon S3, you can get it back from Amazon web console at http://aws.amazon.com. If the file is encrypted, you can download the file first and use open source tools such as OpenSSL to decrypt and get it back.
(4) Am I sharing the same cloud storage account?
All cloud storage providers organize the storage by account. A Cloud gateway vendor may choose to have a one-to-one mapping and pass the account info to you. Another choice is that the cloud gateway vendor may manage the account itself and pool different users into one cloud storage account.
For example, if you decide you want to use Amazon S3 through a gateway, you can ask “Do I get my own Amazon S3 access key and secret key?” or just “Do I get my own Amazon S3 account?”.
Get your own account will enable you to manage files at the cloud storage provider level, even without a gateway.
(5) Encryption? Compression?
All cloud gateway vendors provide encryption and compression. So the question to ask is what algorithm is used. Can I still get my files back independent of the vendor?
If not, is there a stand-alone tool in the public to decrypt and decompress to get the files back.
(6) Fee schedule?
There are basically two camps of fee schedule for cloud gateways.
- variable charge by storage and data transfer
- fixed charge by month or year
You will need to ask and fit your own accounting practice.
These are some basic questions to ask to get you started on the cloud gateways.