VMware VSAN features and realities
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With EVO: RAIL appliances, customers can buy the Virtual SAN (VSAN) packaged with hardware in one hyper-converged bundle -- an option that wasn't available to initial VSAN customers.
Although VMware has pre-certified Ready Nodes that users can install VSAN on, many early adopters built their own VSANs with hardware they already had in house. Those early adopters gave the software high grades for simple management and cost but cautioned others who wanted to build their own VSANs. They found problems with some of the products on the VSAN hardware compatibility list (VSAN HCL), particularly the storage I/O controllers. VMware acknowledges those problems and has taken steps to fix them.
"I had to go from zero to VSAN within three days," said Alan Sprague, systems administrator for information services at Oregon State University's College of Business, in an interview with SearchVirtualStorage. "Now that I know what I'm doing, I could do it in four hours."
Sprague said he doesn't recommend such a speedy implementation, but he only had a week between terms to switch over an ineffective virtual desktop infrastructure (VDI) from local storage to VSAN. At one point, he didn't think he would make it after struggling with storage controllers listed on the VSAN HCL.
"We had some challenges," he said. "There was no cookbook and no good documentation. I built and tore down three or four servers three times over the course of those three days." To get VSAN to read his solid-state drives (SSDs), he had to perform a drive-by-drive low-level wipe across 34 drives.
Once he got it working, VSAN saved the day for his approximately 200-seat VDI implementation that runs in his school's labs. Sprague said before VSAN -- with no SSDs -- it took approximately 20 minutes to refresh the virtual desktops between classes so the next group could log in. Now he said it takes a minute or two. Before the upgrade, "Our VDI was getting crushed and couldn't handle the IOPS load," he said.
VSAN hardware woes are worth the management benefits
Sprague wasn't alone in struggling with compatibility issues when repurposing hardware for VSANs. He was part of a VMworld 2014 panel of early VSAN adopters, and that was a common theme.
Tiemann said he had to go through several products on the HCL to get everything working. Hollis, VMware's chief strategist for storage, admitted he heard similar stories from other early adopters. "That was a consistent experience with everybody early on with VSAN," he said. "We at VMware completely underestimated the complexity involved. It's been corrected, but if you went early, it was no fun at all."
"We built our own, and the takeaway is, while that was painful, you should press your account team on what will be certified," said Michael DiBenedetto, manager of IT infrastructure for Sekisui Diagnostics. "There is setup time involved. If you roll your own [VSAN], get your hardware ready out of the gate."
The panelists all said they were happy they stuck with it and reported positive results after getting their VSAN together. (Not much of a surprise, as the panel was put together by VMware). They described easy maintenance and management for organizations with few or no dedicated storage pros and performance that was more than good enough.
"Once I got over the hardware issues, it worked as advertised," Oregon State University's Sprague said.
Manish Gupta, previous senior IT lead at Purdue Pharma, listed VSAN's positives as its simplicity, scalability and ease of management after implementing a four-node cluster at a remote site. "After initial challenges, it was a simple setup," he said. "Now I don't have to bother my storage administrators constantly to give me a LUN or zone something. You have x86 servers, a bunch of disk, hook them together with a couple of switches, install the software and you're ready to rock and roll. To scale, I just have to add disk for another node. I don't have to buy an expensive array or fully loaded disk shelf. The upfront investment is not that high."
Tiemann said VSANs allow Invesco to replace traditional SANs in regional sites. "I wanted to get our DR [disaster recovery] on a virtual platform," he said. "Now I don't have to have a storage admin up in a colo site. I'm happy with the performance."
Sekisui Diagnostics' DiBenedetto used VSAN as a target for DR and test/dev. He said it's easy to manage, which is important because Sekisui has no dedicated storage person and only two people dedicated to infrastructure.
"Our admins are used to working with x86 servers," he said. He added that VSAN simplifies support because "It's all with VMware, and you don't have to worry whether the problem is with the storage vendor or not."
VSAN wish lists include all-flash, files, reporting
When asked what features they were looking for in future releases, the panelists mentioned file services, support for all-flash systems (VSAN is currently a hybrid configuration), better reporting, and enterprise features such as deduplication and replication.
Alberto Farronato, VMware's director of product marketing, said those were common requests from early VSAN adopters, along with snapshots and stretch clustering. He would not say which of those features will make it into VSAN 2.0, which is now in beta. "As we improve on data services," he said, "that will broaden the spectrum for VSAN."
File services are unlikely to make it into VSAN 2.0. During a VMworld deep dive session on software-defined storage, Farronato called out Maginatics Virtual Filers for VSAN and NexentaConnect as good ways to enable VSAN file services. That suggests VMware won't add those services soon.
"The NAS use case is best addressed by our partners," he said.