– hint: your non-virtualized servers
We all know about the challenges with server virtualization. The highly random workloads that hypervisors create can cause fits for the shared storage system supporting them. However, the unpredictable performance that results from these spikes in storage demand can come from other servers as well. Most environments include a number of non-virtualized or ‘bare-metal’ servers, some of which are fairly large ‘customers’ on the same shared storage infrastructure as your virtual environment. So when you have a problem with storage supporting a virtual infrastructure, the cause can be your non-virtualized servers.
What are the solutions?
To fix a problem with virtual server host performance we can look at beefing up the shared storage system by adding more disk drives or adding flash. We can also look at putting some flash into the host running those VMs. But another option is to look at the other servers, the non-virtualized servers that are also connected to that shared storage array.
These can be the ‘redlining’ servers, those systems that may be past the point where they should have been replaced but tight budgets have kept them in service. These overworked and overloaded servers can have similarly outsized data sets which create spikes in demand for shared storage.
The problem can also be caused by servers supporting cyclical activities like month- or quarter-end reporting, yearly analytics or the holiday shopping season. Since they’re fine most of the year, upgrading these systems can be tough to justify, but when they’re pushed to the limit they can create problems for the rest of the storage environment.
While often discussed as a solution to storage performance problems in a virtual environment, server side flash caching can also be a effective solution in these bare metal situations. Adding a local cache on these servers pulls their demand off of the shared storage array, freeing more resources for the virtualization hosts that may also be experiencing performance problems.
Storage Switzerland and SanDisk held a webinar on which bare metal systems can be causing performance problems for your virtualized environment, and how to address those problems. Everyone who watches can download a copy of Storage Switzerland’s latest white paper “Is Flash Caching for More Than Just Virtualization?”. In addition, all registrants will be able to access Storage Switzerland’s extensive library of on-demand webinars, many with exclusive white papers, without having to re-register.
SanDisk is a client of Storage Switzerland