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VMware made its most significant move into storage in 2014 with its VMware Virtual SAN (VSAN) software that turns x86 servers into hyper-converged systems. VMware made VSAN generally available in March, and added an OEM version called EVO: RAIL later in the year.
VSAN runs on the vSphere 5.5. kernel and pools disk capacity from storage in a cluster of ESXi hosts. Each VSAN node includes solid-state drives (SSD) for read and write caching, as well as hard disk drives for capacity. Customers can build their own VSAN using VMware's hardware compatibility list, get the software pre-packaged on VMware's Ready Nodes or buy it as EVO: RAIL systems from hardware vendors.
Regardless of the way VSAN is deployed, it competes with hyper-converged vendors such as Nutanix, Scale Computing and SimpliVity, as well as storage virtualization software vendors such as DataCore.
As VSAN enters its second year on the market, we’ve compiled a list of the top five VMware VSAN takeaways of 2014.
1. VMware is now a storage vendor
VMware's vSphere always had a big impact on storage, but never before was the vendor a storage provider. Though it's technically not a true SAN -- it can only store virtual machines and can't connect directly to existing physical servers -- it does provide storage capacity along with its hypervisor software. VSAN makes VMware competitive to storage array and software vendors. For example, early storage virtualization vendor DataCore updated its SANsymphony-V software in 2014 with an eye on VSAN.
“Why is VMware doing storage? The answer is simple: Storing and managing data is one of the most critical functions that the data center is responsible for," VMware CEO Pat Gelsinger said during the VSAN launch in March.
2. Support and configuration limitations
An obvious limitation of VSAN is that it's hypervisor-specific to vSphere, but beta testers also reported some hardware compatibility issues at an early users panel at VMworld 2014. While VMware acknowledged the problem and said it was taking steps to fix it, what doesn't help are existing configuration requirements: both flash and disk are required in a VSAN node, but the SSD is used only for caching. According to some analysts, the write caching is an ineffective use for flash. And to scale a VSAN, its disk capacity needs to be added rather than SSD, limiting performance.
3. Preconfigured might be the best bet
Many early adopters built their own VSANs from existing hardware, but there are a few ways VSANs can be implemented, and some make it simpler than others. Customers can use Ready Nodes -- pre-certified storage on which users can install VSAN. Current Ready Node partners include Cisco, Dell, IBM and Super Micro Computer.
Another option is to buy EVO: RAIL from storage and server partners that bundle VSAN software on hardware that meets VMwar’s specs. Dell, EMC, Fujitsu Ltd., Inspur Group Co. Ltd., HP, Hitachi Data Systems, NetApp, Net One Systems Co. and Super Micro Computer have signed on as EVO: RAIL partners.
4. VSAN appeals most to small shops, hyper-converged fans
VMware said from the beginning that VSAN isn't targeted at storage professionals, but rather server admins as a way to get storage without having to provision LUNs and volumes. The pre-packaged options certainly make that easier on both server admins and companies with a limited dedicated storage staff. And early use cases for VSAN seem to fall in line with those of other hyper-converged products -- such as virtual desktop infrastructure environments and remote office.
5. Close, but not quite enterprise-class
VSANs can scale up to 32 nodes -- enough for many but not all enterprise environments. It is also missing features that enterprises require. These include data deduplication, encryption, tiering and continuous data protection. Users have also expressed the desire for an all-flash VSAN option in the future. Some of these features will likely make it into VSAN 2.0, expected in 2015.
VMware Virtual SAN requirements could be too extensive
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