Virtualization helped drastically consolidate servers, as organizations spun up VMs rather than purchasing additional hardware. The next wave of consolidation stemmed from strides in storage and server performance. Solid-state drives now match or surpass hard disk drive capacities and are much faster, while CPU core counts are soaring and dynamic RAM capacity is going through the roof.
For virtualized server farms, the prospect of much more horsepower allows the total count of servers needed for a given workload to shrink substantially. Alternatively, very powerful virtual instances can be assembled to either change how workloads are processed, such as totally in-memory platforms, or allow new workloads, such as compute/memory-intensive scientific apps, to be moved into the virtual space.
THE IMPACT OF SSDS
Not long ago, in order to get adequate performance, a server needed at least six Serial Attached SCSI drives. Today, a pair of NVM Express drives does the same job, with better data integrity. We see the same reduction in networked storage, with performance met by solid-state drives (SSDs) and cold secondary storage supplied by large Serial Advanced Technology Attachment (SATA) hard drives. The writing is on the wall for these SATA hard disk drives (HDDs), with 30 TB 2.5-inch SSDs announced.
SSDs affect more than just capacity, though. SSDs use much less power than HDDs and typically adhere to the 2.5-inch form factor. The M.2 size — formerly known as the Next Generation Form Factor — is typically as small as 22 mm x 30 mm, continuing to minimize the space needed for the drive pool. Taken together, the drive space in servers and storage appliances could drop by as much as 70% from the designs common today.
THE SERVER SIDE
The server side is also evolving rapidly. Thanks to SSDs, CPU improvements are now reflecting a similar — or better — rate of server-level performance boosting.
That’s not all. Memory expansion has led to feasible in-memory databases, which really boost performance in a virtual server cluster. Oracle reports as much as a 100x increase in performance, which either translates into fewer servers needed or a much faster runtime. Either way, organizations will consolidate servers as a result.
HCI aligns well with software-defined infrastructure, which takes advantage of the underlying virtual server structures created by hypervisors to separate control-plane data service software from storage, network and server hardware platforms. With the ability to service many more instances, the next generation of servers will create more room for microservices with all the flexibility that that approach implies.
With a small footprint for these appliances — think of them as Lego blocks — and with all of the factors above pressing on the issue, the future server farm will shrink physically by quite an amount. However, another major factor is in play that takes the shrinkage even further.
HOW TO CHOOSE BETWEEN REPLACING AND UPGRADING SERVERS
One common topic of discussion is whether to upgrade or replace a server. There are a number of factors that go into making this decision. The first is cost — most data centers don’t have an unlimited budget, so administrators need to consider which option is more cost-effective. Although virtualization helps administrators use their hardware resources more efficiently, servers are often expensive, making them difficult to simply replace. Upgrading servers purely for the sake of change is costly as well, and can cause issues in your data center. As a result, the first step to making an informed decision between replacing and upgrading servers is to monitor your preexisting data center.
It’s always important to assess the effects of any change to your environment. When it comes to upgrading and replacing hosts in a virtual environment, having the ability to replace them is the ideal scenario, however, you can avoid an expensive purchase if you can add additional memory to memory constrained hosts. That said, if your servers are CPU-constrained and do not have additional CPU sockets available, replacing the hosts is likely your only option. Replacing hosts is substantially more expensive than simply adding memory, but keep in mind that price is not the only factor to consider when choosing whether to replace or upgrade; you must also consider growth curve and performance.
THE GOAL IS LONGEVITY
When considering upgrading servers, ask yourself, “How long will it be applicable?” Upgrading memory or storage in an environment is only beneficial if the upgrade lasts until your next budget cycle or a planned replacement. Otherwise, all you’ve done is fill a shortage gap that will need to be addressed again in the near future, most likely during an unplanned cycle. This stopgap measure can cost you more in the long run, especially if you have to replace equipment — the cost of the replacement combined with the cost of the original upgrade can amount to a hefty sum. Growth curves can be tricky to track because one large project can greatly affect normal growth trends. However, you can almost always depend on growth to trend upward.
UPGRADING SERVERS AFFECTS PERFORMANCE
Another thing to consider before upgrading servers is what an upgrade will do to overall system performance and reliability. For example, moving a server from spinning disk drives to a solid-state drive can have a tremendous effect on performance if the server is fully capable of using the new hardware. If the server isn’t capable, upgrading may still yield a performance boost, but a much smaller boost than anticipated. The other concern is that improving one aspect of the system might burden the parts that are now trying to keep up with the updated component. This is typical of introducing upgrades to older systems. This kind of change can even affect application behavior and create new bottlenecks in the system.
While many IT folks would always prefer to go with new equipment, upgrades are a necessary part of data center life. The key to a successful upgrade has more to do with its business impact, growth, performance impact and lifespan of the original equipment than the technology itself. Keep all of this in mind and you should have no problem choosing between upgrading and replacing elements of your data center.