Virtual appliance lets users convert DAS to iSCSI San
LeftHand Networks has released an edition of its SaniQ iSCSI San software that will convert locally attached disc to networked storage.
The Virtual Storage Appliance (VSA) is compatible only with VMware's Infrastructure 3 (VI3) and requires two physical ESX servers for failover and mirroring for data protection. LeftHand's software, in virtual as well as physical editions, converts servers, until now hardware boxes from IBM and HP, into iSCSI Sans. What's more, this edition will be no different when it comes to the DAS on the ESX servers, according to vice-president of marketing John Fanelli.
"Nearly all of our users have internal storage that gets thrown in with server purchases, usually somewhere around a terabyte per server, that they're not using," Fanelli said. Before VI3 added iSCSI support, some users were using ESX on big servers, rather than moving to San. Since then, he said, "When users move these big systems to San, they're left asking, 'What do we do with all this storage'?"
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If installed on a server, the full version of the software will automatically see the DAS belonging to its physical host, as well as the storage being managed by SaniQ anywhere on the network, including LeftHand's full San. VSAs and LeftHand's Sans running on server hardware clusters can be managed together from one screen.
According to Tony Asaro, senior analyst with the Enterprise Strategy Group (ESG), "This is the way the whole market's going, with virtualised software sharing various storage and server resources."
But according to Fanelli, this management integration also has to do with the fact that the VSA is not meant to ultimately replace a San. This is due to the performance issues still presented by server virtualisation products that must "switch" between the hypervisor and operating system in order to transfer commands.
Furthermore, some users currently evaluating the VSA said they have concerns about performance.
"Once you put virtual servers on top of a virtual San, there's a definite question as to how it's going to perform," said Stan Rehfuss, director of technical systems and operations for the Denver Museum of Nature & Science. However, he said he sees the VSA system helping out with a disaster recovery plan he's still trying to get off the ground, allowing him to replicate data from a 6Tbyte LeftHand hardware-based San to VSAs at a second location.
Rehfuss also said that he's interested in using the VSA for temporary, cheap expansion of the main San. "It's really hard to go and say you need £50,000 for storage expansion when the whole [IT] budget is a little more than double that."
For other LeftHand users, the ability to repurpose DAS far outweighs any performance concerns. Bob Lamb, general manager of hosting services for managed hosting provider Strategic Business Solutions, said he's been waiting for this product for more than a year. "I plan to use it to offer my smaller clients storage services at a much lower price point than with my physical LeftHand San," he said. He estimates that the new services he will offer, based on VSA, will run about 50p per gigabyte, as opposed to the £2.50 per gigabyte charged now for physical storage. "It'll help my company get into a whole new market."
Jimmy Reid, director of technical operations at the University of Maryland, said in an interview with SearchStorage.com that his shop has been using the VSA since LeftHand released version 7.0 of its SaniQ software and set him up with the feature well in advance of its announcement. The ability to fold unused DAS on physical hosts running VMware "is going to be huge for us," said Reid. "There's almost 2Tbytes that we can immediately start using that's sitting empty in our environment."
The LeftHand VSA requires a base configuration of two physical hosts equipped with ESX server. Each server should have at least 2Gbytes of Ram and 2GHz of CPU reserved through ESX. The VSA itself is priced at £250,000 per instance. Fanelli estimated the cost of the required server hardware at about £5,500 street price. "That's compared to £13,000 on new servers and £8,500 for software to run a physical San," he said.
