Many regular readers will know that we do not do read locality in Virtual SAN. For VSAN, it has always been a trade-off of networking vs. storage latency. Let me give you an example. When we deploy a virtual machine with multiple objects (e.g. VMDK), and this VMDK is mirrored across two disks on two different hosts, we read in a round-robin fashion from both copies based on the block offset. Similarly, as the number of failures to tolerate is increased, resulting in additional mirror copies, we continue to read in a round-robin fashion from each copy, again based on…
As part of the Virtual SAN 6.1 announcements at VMworld 2015, possibly the most eagerly anticipated announcement was the support for a VSAN stretched cluster configuration. Now VSAN can protect your virtual machine across data centers, not just across racks (which was achievable with fault domains introduced in VSAN 6.0). I’ve been hearing requests from customers to support this since the initial VSAN beta, so it is definitely a welcome addition to the supported configurations. The obvious next question is how do I set it up. Well, first of all, you will need to make sure that you have a…
I’ll start this post by stating straight up that I am no OpenStack expert. Far from it. In fact, the only reason I started to play with VMware Integrated OpenStack (VIO) was to get up to speed for a forthcoming OpenStack class that I am taking in next week. What I’ve documented here is a bunch of issues I ran into during the VIO deployment process. Hopefully these will prove useful to some folks who are also new to OpenStack and plan on going through the same exercise. I’m not going to describe VIO in any detail, nor any of…
It’s that time of year once again. The 2014 VMware Fling Contest is now open. Do you have an idea on how certain features or functionality could be improved upon? Can you think of an app that would make the life of a system administrator so much easier? Do you have a repetitive task that you wished you could have automated in your vSphere environment? Or a decision-making tool for certain tasks? We are looking for you, our customers & users, to propose ideas for new VMware Flings. Our panel of judges will pick the winner. Previous winners include the…
A short and sweet post today. In vSphere 5.0, VMware introduced support for 16Gb FC HBAs. However these HBAs had to be throttled down to work at 8Gb. In 5.1, VMware supported these 16Gb HBAs running at 16Gb. However, an important point to note is that there was no support for full end-to-end 16Gb connectivity from host to array in vSphere 5.1. To get full bandwidth, you possible had to configure a number of 8Gb connections from the switch to the storage array. With the release of vSphere 5.5, VMware now supports 16Gb E2E (end-to-end) Fibre Channel. Get notification of…
We at VMware have been making considerable changes to the way that the All Paths Down (APD for short) and PDL (Permanent Device Loss) conditions are handled. In vSphere 5.1, we introduced a number of enhancements around APD, including timeouts for devices that entered into the APD state. I wrote about the vSphere 5.1 APD improvements here. In vSphere 5.5 we introduced yet another improvement to this mechanism, namely the automatic removal of devices which have entered the PDL state from the ESXi host.
I’m delighted to be involved in an upcoming project on vSphere Design Considerations. This is the brain-child of my ex-colleague, Frank Denneman, who recently fu^H^H decided to broaden his horizons and join an interesting new start-up called PernixData. 🙂 Also on the project are Duncan Epping (still a colleague), Jason Nash and the inimitable Vaughn Stewart of NetApp. To cut to the chase, the objective here is to create a pocket-sized book containing the best vSphere design considerations. However, the cool part of this book is that the community are the authors. And the book will be free, courtesy of…