VSAN considerations when booting from USB/SD

This is a conversation that comes up time and time again. It’s really got to do with the following considerations when booting an ESXi host that is participating in VSAN from an SD/USB device::

  1. What should I do for persisting the vmkernel logs?
  2. What should I do about persisting the VSAN trace files?
  3. What should I do for capturing core dumps (PSOD)?

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vSphere 6.0 Storage Features Part 6: action_OnRetryErrors

In vSphere 6.0, an improvement has been made to how we handle I/O issues, such as flaky drivers, misbehaving firmware, dropped frames, fabric disruption, dodgy array firmware, and so on which can cause I/O failures. The issue is that, previously, we continually retry these sorts of I/O errors, which can lead to all sorts of additional problems. In this release we are changing our behaviour for marking a path dead.

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vSphere 6.0 Storage Features Part 5: Virtual Volumes

VVolsI pushed this post out a bit as I know that there is a huge amount of information out there around virtual volumes already. This must be one of the most anticipated storage features of all time, with the vast majority of our partners ready to deliver VVol-Ready storage arrays once vSphere 6.0 becomes generally available. We’ve been talking about VVols for some time now. Actually, even I have been talking about it for some time – look at this tech preview that I did way back in 2012 – I mean, it even includes a video! Things have changed a bit since that tech preview was captured, so let’s see what Virtual Volumes 2015 has in store.

Much kudos to my good friend Paudie who did a lot of this research.

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vSphere 6.0 Storage Features Part 4: VMFS, VOMA and VAAI

VMFSThere was a time when VMFS was the only datastore that could be used with ESXi. That has changed considerably, with the introduction of NFS (v3 and v4.1), Virtual Volumes and of course Virtual SAN. However VMFS continues to be used by a great many VMware customers and of course we look to enhance it with each release of vSphere. This post will cover changes and enhancements to VMFS in vSphere 6.0.

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ESXi 5.5 EP6 is now live. Important patch for VSAN users

I wouldn’t normally call out new patch releases in my blog, but this one has an important fix for Virtual SAN users. As per KB article 2102046, this patch addresses a known issue with clomd. The symptoms are as follows:

  • Virtual machine operations on the Virtual SAN datastore might fail with an error message similar to the following:
create directory <server-detail>-<vm-name> (Cannot Create File)

The clomd service might also stop responding.

  • Virtual SAN cluster might report that the Virtual SAN datastore is running out of space even though space is available in the datastore. An error message similar to the following is displayed:
There is no more space for virtual disk .vmdk. You might be able to continue this session by freeing disk space on the relevant volume, and clicking _Retry. Click Cancel to terminate this session.

The clomd service might also stop responding.

While the clomd issue is easily addressed by restarting the clomd service, consider deploying this patch during your next maintenance cycle to avoid this annoyance, or if you re considering a new VSAN deployment, definitely consider using this latest version of ESXi 5.5.

vSphere 6.0 Storage Features Part 2: Storage DRS and SIOC

We made a number of enhancements to Storage DRS in vSphere 6.0. This article will discuss the changes and enhancements that we have made. There is a white paper which discusses many of the previous limitations of Storage DRS interoperability and I’d recommend reviewing it. Although a number of years old, it highlights many of the Storage DRS interoperability concerns. As you will see, a great any of these have now been addressed, along with some pretty interesting feature enhancements.

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A brief overview of new Virtual SAN 6.0 features and functionality

The embargo on what’s new in vSphere 6.0 has now been lifted, so we can now start to discuss publicly about new features and functionality. For the last number of months, I’ve been heavily involved in preparing for the Virtual SAN launch. What follows is a brief description of what I find to be the most interesting and exciting of the upcoming features in Virtual SAN 6.0. Later on, I will be following up with more in-depth blog posts on the new features and functionality.

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