Archive
Posts from 2017
One of the best docker resources on the interwebs
For the past two years I've scoured the official docker documentation when I needed to learn something. Their documentation is really good but there are areas that lack examples and a deep explanation of why something is the way it is. One of my goals for this year is to read one technical book / RFC a month so I decided to start off the year with James Turnbull's The Docker Book. James starts with the basics and then extends this with a thorough description of images, testing with docker and orchestration…
$ read more →Using the vSphere flash read cache feature to speed up sequential reads
Duncan Epping gave a great overview of vSphere's flash read cache feature and I wanted to take it for a ride. This feature reminds me of the ZFS level-2 ARC which allows SSD drives to be used as read and write caches. The vSphere vcache only provides read caching but that is still super useful for read-intensive workloads. To see how it performed I broke out my trusty old sequential read script to get a baseline: Not too shabby for my old rusty NFS datastore…
$ read more →The power of locality in VMware vSphere environments
I was doing some network throughput testing last weekend and wanted to see how much locality played into virtual machine deployments. The VMware virtual vmxnet3 network adapter is capable of 10Gb/s+ speeds and was designed to be extremely performant. To see what kind of throughput I could get over a 1Gb/s link I fired up my old trusty friend iperf and streamed 6GB of data between VMs located on different ESXI hosts: This was about what I expected given the theoretical maximums of 1Gb/s copper l inks. To see how things performed when both VMs were co-located I vmotioned one of the servers and re-ran the test: The vmxnet3 adapter is not just capable of pushing 10Gb/s it is capable of pushing data as fast as the motherboard and chip set allow…
$ read more →