Why – and how – should I switch my business to virtual servers?
With servers increasingly sold as a service, rather than a piece of on-site hardware, is it time to shift?
The traditional way of running server apps loading up your hardware and locking it away in a dark room is beginning to look old-fashioned. Many companies have made the switch to virtual servers, maintained at a remote location by a specialist third party, so the question arises: should you? And if so, when?
What is a virtual server?
A virtual server isn't just a place to host your website, although that could be one of its functions. It's a virtualised environment, effectively a computer in the cloud running Linux or Windows, which can be networked with other virtual servers to hugely scale its computing power. This is one of the primary benefits of opting for a virtual rather than dedicated server, where the limits of what it can do and how far it can scale are determined by its immutable hardware specs.
The efficiencies don't stop there: they can impact a firm's bottom line too, as a virtual server can deliver significant savings.
"We have customers who only need the full power of our platform at the weekend," explained Alexander Vierschrodt, head of global product management for 1&1's cloud server business.
"They're running a soccer app that pushes notifications to their customers, so if a game is on at the weekend during the regular season, they scale up by a factor of ten to 50 virtual machines; as soon as match day is over, they go down to around two virtual machines and save around 70% of the cost of a dedicated server."
This performance guarantee, and the ease with which suppliers can reallocate resources to meet it, is in contrast to a shared hosting system. There, sites sitting side by side even though they're assigned to different accounts are competing for the same resources. "If somebody gets a spike in traffic, everybody on that server will feel the effect," said Stuart Melling, co-founder of 34SP.com in Manchester.
This isn't the case with a virtual server because the resources allocated to each user are guaranteed. "If there is a spike in traffic, it's contained within that single instance, and we can quickly scale up a customer's resources if they need it," said Melling. "One of our clients was recently on The One Show, and he called to warn us, so we quickly scaled up his VPS [virtual private server] and it was fine, coping with the BBC1 prime-time audience hitting his site all at once."
Memset's Nathan Johnston added: "There's strong separation within the virtualisation software that protects you from noisy neighbours. If somebody else is trying to use more resources than they've been allocated, the hypervisor layer won't allow that; in the same way that if you have a security incident on one machine, it isn't going to be able to break out to another. Each virtual machine has its own kernel and operating system."
Opting for a virtual server rather than self-hosting or upgrading to a dedicated host, which Johnston describes as being equivalent to using a sledgehammer on a walnut, provides the freedom to change your setup on a whim and even, with a little more work, your provider.
Many cloud-hosting providers run VMware-based systems, meaning it's possible to create an image on one and deploy it on a rival's hardware. Vierschrodt sees this as a benefit of VMware, on which the company rolls out bespoke server configurations for its customers, allowing them to choose a common LAMP (Linux, Apache, MySQL, PHP) stack, or exotic lineups for specific applications.
Another option is Docker. "[Docker provides] a way of making an image that can be moved between different kinds of containers," said 34SP.com's Melling, "from one of our servers to, say, Amazon cloud." For a growing startup, the freedom to move in this way could prove a tempting proposition, with Amazon's block-based billing scaling to reflect the startup's increasing popularity.
Virtual vs dedicated
There's no single transition point that would suit all companies wondering when they should step up from a virtual to a dedicated server, and many providers including both Amazon and Microsoft only offer a virtual product.
According to Johnston, one metric is the intensity with which a customer uses its host's disk resources. "With SAN-based virtual servers, it's sometimes quite difficult to get guaranteed disk performance, and should you have a very large database application that's retrieving and sending information to a web server. At that point it's best to go for a dedicated server, because you're going to get all the disks on that machine, without sharing them with anyone else; [but even then you should] go for a mixture of virtual servers and dedicated."
"The only thing that would make me move to a dedicated system is if I had the same workload day in, day out because a dedicated server does not scale," explained Vierschrodt. "You get the same power every day and you have to pay for that power. So, if you [always] have the same workload, it might be a little cheaper to go with a dedicated server, but as soon as you have to scale, a cloud server always makes sense."
"The dedicated server presents you with a curious problem," said Melling. "Once you hit its limits, that's it. You would do better to scale vertically [as you can with a virtual server], but you have to scale horizontally, where instead of having one powerful box doing everything, you have multiple smaller boxes doing different things simultaneously."
In this scenario, a customer would split its services across multiple servers, handling its website, database and email individually. As Melling highlights, though, there's little functional difference between doing this and renting several discrete containers on a virtual server setup, the latter of which would be cheaper.
"It's always best to get slightly more resources then you need, just because it's going to be snappier and provide better performance," said Johnston, who likens investing in a virtual server to buying a new vehicle. "If you want to cruise on a motorway at 80mph, it's much more comfortable to get a car that can do 120 rather than a car that can do 90: you're not going to be struggling all the time."
Remember, though, that by offloading responsibility for your server to a third-party provider, you're not only buying into its hardware, but also its expertise. "If a business has a telephone they're more than happy to pay 75-a-month line rental, but when you tell them they should be spending similar if not more on their website, they question why they shouldn't just be paying $3 a month," said Melling.
"If you're making any appreciable amount of money [through your website or hosted application], you want to look at what you're spending and ask whether you'd do that with anything else [that's mission critical] in your business... if you're paying just a few pence per day, how much can your host really afford to invest in supporting your business?"
Main image credit: Bigstock
This article originally appeared in PC Pro
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