The Windows Server 2012 release arrived last month with a slew of storage-related functions and features, many of them tied to large Hyper-V installations, and many of them promising
"These are massive changes," said Stephen Foskett, a storage industry analyst who is also a Microsoft MVP. Foskett said he was "skeptical" when he first met with Microsoft and heard ambitious plans for storage technology in Server 2012. "I was really shocked they made the final cut."
Still, Foskett isn't arguing that some of the much-hyped new Windows Server 2012 storage features -- such as deduplication -- are going to change the way storage managers rely on current technologies or providers.
"Microsoft did a very good job, technically, of implementing dedupe; it's world class and it's very solid. But it really only works for file server workloads," Foskett said. "So Microsoft should be congratulated for reducing storage needs for file servers, but it's not going to change the workload. Most people are still going to be buying Data Domain, for example."
Chris Evans, a U.K.-based storage industry expert who runs a home lab that has Server 2012, expressed a different view in an email yesterday. The deduplication feature -- which allows users to save disk space by storing a single copy of identical data on the volume -- should rank among the most interesting features for storage managers, he said. "This enables storage to be utilized much more efficiently, especially with virtual machines under Hyper-V. The nice thing about using this feature is it translates to direct cost savings to customers.
One new Windows Server 2012 feature Foskett and Evans agreed on was the power of ReFS, the Resilient File System in Server 2012. "This allows for much larger scaling on logical volumes, and when combined with Storage Spaces, it gives better availability -- and an attempt to deliver no downtime even with data corruption," Evans said. "It's another feature that provides a solid foundation for deploying large-scale Hyper-V configurations."
Storage Spaces, targeted at storage pros, is Microsoft's name for storage pooling functionality in Server 2012. Microsoft describes it as a way for users to virtualize storage by grouping industry-standard disks into storage pools and then creating storage "spaces" from the available capacity in those storage pools. On this point, Foskett was less enthusiastic than Evans.
"It's a very good addition for Windows, but it's not quite to the level that [Symantec's] Veritas Volume Manager is in terms of high availability," Foskett said. "It was designed for small-ish use cases. It's more of a convenience feature than a real enterprise storage manager feature.
"Still," said Evans, "customers get a lot more flexibility when using internal disks."
Brien Posey, also a Microsoft MVP and industry expert, explained how Storage Spaces operates in a recent SearchVirtualStorage.com expert tip: An administrator defines a storage pool consisting of physical disks, allowing Windows to write pool-specific metadata to each disk in the pool. That way, each physical disk can be uniquely identified within the pool.
Once the storage pool has been created, administrators are free to begin creating virtual hard disks within the pool. These virtual hard disks can appear to the operating system as a physical disk even though a virtual hard disk can easily span multiple disks.
Posey argued that Storage Spaces is about more than just the creation of hard disks. For starters, he wrote, Windows offers a number of RAID-like features to improve a virtual hard disk's resiliency. For example, a virtual hard disk can be mirrored or striped with parity. This can prevent data loss in the event that a physical disk within the pool fails, he wrote.
Server Message Block 3.0 support
Windows Server 2012 has added support for Version 3.0 of the SMB protocol. It's positioned as an alternative to Fibre Channel and iSCSI, Foskett said. "The key is that SMB 3.0 is revved to support application workloads and not just client connections," he explained. "It makes Server 2012 a valid client as well. That's for Hyper-V, SQL Server and Exchange. We've never really used NAS for applications in Windows.
"Not only is it a big move forward technically -- in terms of protocol enhancements -- it also has a big impact on the rest of the stack. This is important for the industry; it's also important for Microsoft," Foskett said.
"If you can imagine that Microsoft can support Hyper-V, you can use Windows File Server as the target. You don't need iSCSI or Fibre Channel as the target. Microsoft is trying to capture more of the revenue in the data center, and this is how they are going to do it."
Foskett acknowledged storage administrators might be slow to adopt SMB 3.0, since it's the grandchild of common internet file system (CIFS), a term and technology that brings back painful memories to many veteran storage administrators.
Microsoft has some work to do educating customers, Evans added. "I think people don't understand that SMB 3.0 has become a much better NAS protocol than the early days of CIFS. Many end users probably still see it as an inefficient, chatty protocol. That's no longer the case as improvements have been made over time."
iSCSI Target Server
Some storage pros might know iSCSI Target Server as part of the OEM version of Microsoft Windows Storage Server. Essentially, it provides block storage to other servers and applications on the network by using the iSCSI standard. "The big news here is that iSCSI Target is now available for Windows Server customers, not just OEM customers," Foskett said. "So previously there was no way an average Windows admin could get it. But now they can download it; they can basically have an iSCSI array."
That could be especially useful if adoption of SMB 3.0 is slow, he said.
Evans was a bit more wary of the new iSCSI capability. "The iSCSI target is also a useful feature, but it's functionality is still quite limited. Other players in the market offer much better functionality and features," he said.
Offloaded Data Transfer
"The Hyper-V people have long wanted something like VAAI [vStorage APIs for Array Integration, functionality in VMware's vSphere] and now the whole Windows Server world gets it," said Foskett of Offloaded Data Transfer, or ODX. VAAI enables offloading of storage-related tasks from the hypervisor to the storage array. "No other operating system has anything like this. It accelerates copy and thin provisioning operations by offloading them to a compatible storage array. It's not something that people are giving a lot of attention to now … but a year from now it will have broad support from array vendors," Foskett predicted. "Then, when a storage user copies a file, the transfer will be much quicker because the array will do the work instead of sending the data all the way up through the operating system."
Storage pros should be asking their vendors about ODX, said Evans, for two reasons: "First, ODX functionality will become much more important over time, and if customers aren't asking for it, it's never going to get implemented."