
How to speed up your X-ray benchmark development cycle by re-using/re-cycling benchmark VMs and more importantly data-sets.
Continue readingHow to speed up your X-ray benchmark development cycle by re-using/re-cycling benchmark VMs and more importantly data-sets.
Continue readingHow to ensure performance testing with diskspd is stressing the underlying storage devices, not the OS filesystem.
Continue readingHow to install and setup diskspd before starting your first performance tests and avoiding wrong results due to null byte issues.
Continue readingTo achieve the maximum throughput on a storage device, we will usually use a large IO size to maximize the amount of data is transferred per IO request. The idea is to make the ratio of data-transfers to IO requests as large as possible to reduce the CPU overhead of the actual IO request so we can get as close to the device bandwidth as possible. To take advantage of and pre-fetching, and to reduce the need for head movement in rotational devices, a sequential pattern is used.
For historical reasons, many storage testers will use a 1MB IO size for sequential testing. A typical fio command line might look like something this.
fio --name=read --bs=1m --direct=1 --filename=/dev/sdaContinue reading
How to avoid bottlenecks in the client generator when measuring database performance with HammerDB
Continue readingA 2007 paper, that still has lots to say on the subject of benchmarking storage and filesystems. Primarily aimed at researchers and developers, but is relevant to anyone about to embark on a benchmarking effort.
The authors are clear on why benchmarks remain important:
“Ideally, users could test performance in their own settings using real work- loads. This transfers the responsibility of benchmarking from author to user. However, this is usually impractical because testing multiple systems is time consuming, especially in that exposing the system to real workloads implies learning how to configure the system properly, possibly migrating data and other settings to the new systems, as well as dealing with their respective bugs.”
We cannot expect end-users to be experts in benchmarking. It is out duty as experts to provide the tools (benchmarks) that enable users to make purchasing decisions without requiring years of benchmarking expertise.