Though products such as VMWare ESX and Microsoft Hyper-V have made it possible for companies to virtualize their servers, it’s not so easy to virtualize disk, tape and storage resources, according to speakers on a recent webinar.
Different vendors manage their storage in different ways, said John Sloan, senior research analyst at London, Ont.-based Info-Tech Research Group.
“Storage virtualization is not as cut and dry as server virtualization is,” he said. “You can’t just mix and match storage modules. There’s usually one standard on one vendor.”
Jim Decaires agreed.
“Virtualization does not free you from your vendor dependence,” said Decaires, storage product manager with hard disk drive manufacturer Fujitsu Canada Inc., who also spoke on the webinar, held Wednesday.
The webinar, dubbed Achieve more with less with your storage infrastructure, was hosted by IT World Canada editor-in-chief Shane Schick. Attendees were asked about their level of storage virtualization.
Nearly 46 per cent said they “are currently evaluating storage virtualization solutions” while 18.9 per said they are actually using the technology. Nearly a third – 29.7 per cent – said they have no requirements or plans to implement storage virtualization.
Sloan said companies surveyed by Info-Tech are telling him they want virtualized storage for one of two reasons. Either they want to streamline and consolidate infrastructure because they have “too many islands of storage” or they want to make sure they can extend availability and recoverability to as many servers and applications as they can across the infrastructure.
Decaires said there are two main types of storage virtualization: in-band, or symmetric; and out of band, or asymmetric.
Though it has bandwidth limitations, in-band virtualization sends all metadata to a virtualization engine and is easier to manage, Decaires said. But he added it increases the risk of a single point of failure. With out of band, Decaires said, the metadata is split apart from data, is more complex but doesn’t have the same bandwidth limitations at in-band.
When selling storage, Fujitsu asks customers how much capacity they want to virtualize.
“If it’s over 2 petabytes than I will sell you a virtualization product,” Decaires said. “If it’s less, then my experience is the best solution is to buy basic storage products.”
Decaires said users should look for features such as Massive Array of Idle Disks (MAID), wide-area network (WAN) optimization and encryption.
With MAID, he said, users can save power and money by stopping drives when they’re not using them. But not all webinar participants were interested. Only 5.8 per cent said they could see MAID being utilized within their data centre, while 41.1 per cent said they like the idea but don’t have the time or resources to integrate it. Nearly a third – 32.3 per cent – said they don’t need MAID while 20.5 per cent said they are interested but are concerned about the reliability of spinning down drives.
WAN optimization includes compression, de-duplication and acceleration, and helps save money, Decaires said because some users need to move data over hundreds of miles.
“Bandwidth is one of the biggest expenses in your data centre when you’re moving data over distances,” he said.
Sloan said Fiber Channel users doing replication between sites may want to consider looking for optimization technology from their storage vendor, but Ethernet users may want a separate WAN optimization appliance.
Decaires said encrypting data at the storage level can help save money.