At VMworld last year, Duncan Epping and I presented on the power of Storage Policy Based Management (SPBM for short). You can find all of the slides and recordings here. One of the demos we used in the presentation was deploying virtual machines via vRealize Automation, and showing how to consume a storage policy on vSAN. This was using a vRealize Automation plugin, and to be honest, it was a little bit challenging to get it to work. And it wasn’t really a VMware plugin per-se, but something developed by our field team. Today, I’m pleased to announce that we…
Degraded Device Handling (DDH) or Dying Disk Handling as it was formerly known, is a feature that has been available in vSAN for some time. However, I regularly get questions about how it works. The DDH behavior has changed significantly over various versions. We may as well begin this post with an overview about the purpose of DDH and then get into the different sort of behaviors. First of all, the reason behind a feature such as DDH is to help avoid cluster performance degradation due to an unhealthy drive. In the early days of vSAN, we had come across…
I had a very interesting question recently about how vSAN handles a failure in an object that is running with an erasure coding configuration. In the case of vSAN this is either a RAID-5 or a RAID-6. On vSAN, a RAID-5 is implemented with 3 data segments and 1 parity segment (3+1), with parity striped across all four components. RAID-6 is implemented as 4 data segments and 2 parity segments (4+2), again with the parity striped across all of the six components. Now, on vSAN, RAID-5 requires 4 physical ESXi hosts for implementation, with each host backing one set of…
I am delighted to announce the availability of our newly updated VMware vSAN 6.7U1 Deep Dive book. This is the 3rd edition of the book. As the title states, this book’s content has been updated to include information about the latest version of vSAN, which is of course 6.7U1. Much thanks to my good friend and co-author, Duncan Epping. As well as doing his share of the content, Duncan took care of all of the admin to get the book available online, something I have no clue about. Thanks man! Also a great big shout out to both Pete Koehler…
At VMworld 2018, one of the sessions I presented on was running Kubernetes on vSphere, and specifically using vSAN for persistent storage. In that presentation (which you can find here), I used Hadoop as a specific example, primarily because there are a number of moving parts to Hadoop. For example, there is the concept of Namenode and a Datanode. Put simply, a Namenode provides the lookup for blocks, whereas Datanodes store the actual blocks of data. Namenodes can be configured in a HA pair with a standby Namenode, but this requires a lot more configuration and resources, and introduces additional…
A very quick heads-up to let you know about an issue some of us experienced with vSAN 6.7U1 and about how to resolve it. We noticed that after upgrading to vSAN 6.7U1, the new Capacity History view did not work. However brand new installs of 6.7U1 worked just fine. The error that one gets from trying to look at the capacity history is “Unable to query charts data for capacity history” as shown below: I’m pleased to report that we have a solution for this issue already. It was caused by an inability to update the database schema in the…
Most readers will be aware that vSAN version 6.7U1 was recently released. For those of you who wish to know more about the release, I wrote this blog article last month detailing the new features. In this post I want to cover an item which many of you may not be aware of. It is a new feature which makes the most common vSAN advanced options visible and configurable in the vSphere UI. There are 3 advanced options which we have surfaced up. The first is the VSAN.ClomRepairDelay timer which is the delay used before rebuilding ABSENT components. The second…