July 31, 2013
Although the term “cloud SAN” makes it sound like you can plug your iSCSI or Fibre Channel connectors into your router and access block-level storage in a remote data center, we’re not there yet. But with some local storage and cache configured correctly, cloud SAN providers offer unlimited capacity for less active data. Customers drastically reduce their on-premises storage hardware needs and pay only for the storage actually used.
“You can call a cloud SAN an oxymoron,” says Jim Bagley, senior analyst at StorageStrategies Now. “The term ‘SAN’ implies a block-storage device connected via iSCSI or Fibre Channel, but ‘cloud’ implies an object store you connect to over Internet protocols. The trick is local storage hardware or a VM-type appliance that makes servers think they’re talking to a SAN.”
“A cloud SAN uses the cloud as primary storage rather than just for backup or archiving … The hybrid architecture gives local storage for speed and infinite remote storage.” George Crump, Lead Analyst, Storage Switzerland LLC
This oxymoron has become a must-have for resellers. “If you’re not leveraging a cloud SAN in some way, you’re behind,” says Bagley. “If you have the expertise to sell any SAN, you have the expertise to sell a cloud SAN.”
Now that companies are used to sending backups to the cloud, active cloud storage is the next step. “StorageCraft [in Draper, Utah] set up its own system so resellers and MSPs can resell cloud SAN storage,” continues Bagley. Dallas-based SoftLayer, now being acquired by IBM, “does a huge amount of white-label business.”
There are a number of players in this market ready to support resellers, according to Bagley, who notes that Natick, Mass.-based TwinStrata Inc. was one of the earliest in the market. Others include Nasuni Corp., also in Natick, and Panzura, of Campbell, Calif. And you can download the software to run a cloud SAN from Amazon Web Services for free if you’re interested in trying out the technology before you contact any vendors.
George Crump, lead analyst at Storage Switzerland LLC, uses a solution from TwinStrata in his company. “A cloud SAN uses the cloud as primary storage rather than just for backup or archiving, which have been popular,” says Crump. “The hybrid architecture gives local storage for speed and infinite remote storage.” Caching is the key, according to Crump, who says, “If you design it right you should have full-speed access locally and a near-infinite amount of total capacity.”
The cache needs to be configured properly, however. If a server’s cache for local storage is too small, the performance penalty isn’t too onerous. But a cache hit on a cloud SAN sends you across the Internet for the data. “Individual records and small files come back fast,” says Crump, “and users won’t even flinch if it takes an extra second or two.” His advice: Set the local cache to hold all active data, plus some extra room.
When files hit the local storage, they are replicated out to the cloud portion of the SAN immediately. Virtual machine server snapshots can be moved off-site at regular intervals, as quickly as every 15 minutes in the case of the TwinStrata solution. Crump has such confidence in his off-site data access he doesn’t bother to use any type of drive redundancy locally. “If our drive fails, we’ll replace it and either tell the service to send all the local data back, or just download records and files as needed.”
“Fifty to 90 percent of all data stored on-premise is passive data,” says TwinStrata CEO Nicos Vekiarides. “Companies have to keep it for compliance reasons, but it’s seldom accessed, so it’s good to move it from the data center floor to the cloud. Then your storage is maintenance free, there’s no hardware replacement worries, no administration.”
TwinStrata’s CloudArray product line “looks like a local iSCSI interface,” says Vekiarides. A new product feature is support for NAS, including Server Message Block, CIFS, and Active Directory integration. About half of TwinStrata’s business goes through the channel, and the company prefers that the reseller provide the hardware to support the CloudArray software, although the company does sell preconfigured hardware appliances.
Details vary, but all vendors offer encrypted links to the storage service center, encrypt the data before transmission, and give encryption keys to the customer. That means the service has no access to data anywhere in the chain.
“There are two costs to consider,” says Bagley. “If you are renting storage space, somebody is making some margin on that, and there may be a point [when] remote storage rental costs add up to more than local storage costs. Second, how responsive the cloud SAN is to local systems will depend on bandwidth, and you’ll be paying to upgrade your bandwidth to access that data.”
On the other hand, many companies use a cloud SAN to replicate virtual server snapshots, which can be spun up as servers with the right cloud SAN back end. The cost of disaster recovery disappears almost completely when virtual machines can run in the cloud SAN data center in case of a local disaster. “Use of a cloud SAN can go beyond backup and become true DR,” says Bagley.
Size of restoration files to return to the local data store can be an issue for some users. “We make videos at trade shows,” says Crump. “While editing, you want to keep the file local, since it might be a terabyte of raw data. If we need it again to create a new clip after it’s off-site, not having instant retrieval is not a problem.”
The cloud train will not slow in the future, and should actually speed up. “The current market size is about $10 billion for capacity optimized storage,” says Vekiarides. “Most is not going to the cloud now, but most should be.”
“Some aspects of a cloud SAN seem too good to be true,” says Bagley. “Lots of smart people are working in this cloud space, and they all need channel partners to reach customers.”