Before I left for PTO, I wrote an article on a number of different storage vendors you should be checking out at this year’s VMworld 2013. One of these was a new start-up called PernixData. With tongue firmly in cheek, I suggested that PernixData might use VMworld as a launchpad of their FVP (Flash Virtual Platform) product. Well, needless to say, my good friend Satyam Vaghani, CTO at PernixData, reached out to me to say that they were in fact announcing FVP before VMworld. He shared some details with me, which I can now share with you if you haven’t heard about the announcement.
This is something which has come up numerous times, and behavior which many of you have observed. There seems to be some issue with uploading files to a VMFS datastore. In fact, in one example, we had someone report that it took 10 minutes to upload a Windows 7 ISO to an iSCSI datastore and less than 1 minute to upload the same ISO to an NFS datastore. Both datastores were very healthy and fast, and both had running VMs on them. There have been variations of this behavior reported before. This post will try to explain why. Continue reading
This is a query which has come up on numerous occasions in the past, especially in the comments section of a blog post on debunking SIOC myths on the vSphere Storage Blog. This post is to highlight some recommendations which should be implemented when you have a storage array which presents LUNs which are spread across all spindles, or indeed multiple LUNs all being backed by the same set of spindles from a particular aggregate or storage pool.
I have had a few occasions recently to start using vscsiStats. For those of you who may be unfamiliar, this is a great tool for virtual machine disk I/O workload characterization. Have you ever wondered about the most common I/O size generated by the Guest OS? What about the latency of those I/Os? What about checking to see the I/O generated by a Guest OS when it is in a so-called ‘idle’ state? vscsiStats can help with all of these queries, as well as providing some excellent troubleshooting options. The tool has been around since the ESX 3.5 days. This blog will take you through some of the steps in getting started with vscsiStats. Continue reading
A number of you have reached out about how to change some of the settings around path policies, in particular how to set the default number of iops in the Round Robin path selection policy (PSP) to 1. While many of you have written scripts to do this, when you reboot the ESXi host, the defaults of the PSP are re-applied and then you have to run the scipts again to reapply the changes. Here I will show you how to modify the defaults so that when you unclaim/reclaim the devices, or indeed reboot the host, the desired settings come into effect immediately.