VMware vSphere Enterprise Plus: An El Reg deep dive
Trevor Pott feels the big business end of virtual machine giant
Hand over the network switch's keys to software robots
Software-defined networking is the feature bump of the now. Having spent a decade building a software suite that renders a lot of operations management software – not to mention systems administrators – moot, VMware is leading the charge to commoditise enterprise networking. VMware's vision is that of a software-defined data centre; this is territory I've covered before and don't see a particular need to rehash.
Even if you don't buy into VMware's grand vision of the future, however, network IO control and distributed switches are things that become indispensable at scale. When your network gets large enough, you start actually using the features on your switches. VLANs are everywhere today, but rate limiting, 802.1p tagging, and teaming/link aggregation all start to be considerations as soon as your network has even one oversubscribed link.
vSphere's network IO control allows you to configure this per VM while the distributed switch ensures that your settings move from host to host with the VM. It's an interesting toy at the scale of my lab. It's useful when I start working with 25 hosts. Working without it would be maddening long before I hit 50 hosts. The networking features make Enterprise Plus worth considering for midsize organisations, and essential for large enterprises.
Storage - appliance, APIs, distributed resource scheduler (DRS) and profile-driven storage
If reshaping the networking landscape is what is going to occupy us all for the next few years, innovations in simplifying and amplifying storage are at the core of the next major wave of changes in IT. VMware and storage have a complicated relationship; majority ownership by big daddy EMC means that VMware walks a fine line between building bleeding edge functionality into their product and invalidating the business model of their parent company.
This has had mixed consequences. An example of how this has worked out well is the VDP backup software discussed above. VDP is EMC technology, and good tech at that. The other side of this particular coin is the vSphere Storage Appliance (VSA).
Fundamentally, it is a truly excellent piece of software. It takes a bunch of local storage (significantly cheaper than centralised stuff) and lashes it together into a distributed storage array that behaves like centralised storage. It creates a local RAID within each node and it mirrors that information to another node within the cluster; great stuff.
Unfortunately, it only supports clusters of three nodes (though you can have as many storage appliance clusters as you want). While this is peachy for small deployments, this is nowhere near the kind of scalability we need in order to challenge the high cost of traditional SANs. VMware has been discussing a grown-up version of this (dubbed vSAN), however, we've only seen a product demonstration so far; it may never be a real product.
Excepting in rare circumstances – such as the desire or requirement to punt a small pod of three servers into a branch location somewhere – the Storage Appliance is functionally useless to enterprises. Enterprises are already likely heavily invested in SANs, so that isn't a big deal. For mid-sized companies, it is a frustratingly tantalising technology. One of the most frequently expressed opinions I have heard from this group is the desire to see the storage appliance capable of scaling as their business grew; they have no interest in SANs.
This isn't to say that VMware isn't innovating in the storage arena; the Storage API can do wonders. Profile Driven Storage (PDS) alone is worth the cost of Enterprise. In a nutshell, PDS allows you to connect up all sorts of different storage and designate the data stores to different tiers. Your VMs can be assigned to these tiers and they will thus only be moved to storage of the quality and speed for which they are optimally designed. Storage DRS is the widget that automates all of that.
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