Migrations and Virtual Volumes – Deep Dive

VVolsRecently I published an article on Virtual Volumes (VVols) where I touched on a comparison between how migrations typically worked with VAAI and how they now work with VVols. In the meantime, I managed to have some really interesting discussions with some of our VVol leads, and I thought it worth sharing here as I haven’t seen this level of detail anywhere else. This is rather a long discussion, as there are a lot of different permutations of migrations that can take place. There are also different states that the virtual machine could be in. We’re solely focused on VVols here, so although different scenarios are offered up, I highlight what scenario we are actually considering.

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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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vSphere 6.0 Storage Features Part 3: MSCS Improvements

icon_clusterOK – not storage improvements per-se, but I got into the habit of documenting our Microsoft Clustering Services (MSCS) improvements some time back, and habits die-hard. Many of our customers continue to run Microsoft Clustering Services (MSCS) on top of vSphere. This is well-recognized, and VMware continues to improve and add features around this for our customers. vSphere 6.0 is no different, with a selection of improved functionality around MSCS on vSphere.

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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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