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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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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VSAN Troubleshooting Case Study

vsan-vmware-virtual-san-boxI have been doing a bunch of stuff around disaster recovery (DR) recently, and my storage of choice at both the production site and the recovery site has been VSAN, VMware Virtual SAN. I have already done a number of tests already with products like vCenter Server, vCenter Operations Manager and NSX, our network virtualization product. Next up was VCO, our vCenter Orchestrator product. I set up vSphere Replication for my vCO servers (I deployed them in a HA configuration) and their associated SQL DB VM on Friday, but when I got in Monday morning, I could not log onto my vCenter. The problem was that my vCenter was running on VSAN (a bit of a chicken and egg type situation), so how do I troubleshoot this situation without my vCenter. And what was the actual problem? Was it a VSAN issue? This is what had to be done to resolve it.

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VMworld 2014 – Storage News Part 2

VVolsI guess the next big tech preview at this year’s VMworld was around Virtual Volumes. Yes, we’ve done this before, but this year there were so many vendors showing demos of their VVol implementation, and so many presentations/sessions on the topic that I believe folks are beginning to realize that we are very close indeed to finally having this feature ready. It’s hard to believe that this was first discussed at VMworld 2011, and I alluded to this when I presented a VVol session that I co-delivered with the folks from Nimble Storage at this year’s VMworld.

This topic is going to be huge, and it is going to change the way storage is designed for virtualization environments. And I think almost every storage partner I spoke to at the show is on-board. In fact, “The Register” asked the question last month if there was ANY storage vendor that wasn’t doing a VVol implementation?

I’m not going to get into any technical details of Virtual Volumes in this post – there will be lots of time for this later. Instead, I’m going to share how we believe VVols will now enable Software Defined Storage (SDS) for SAN & NAS arrays, similar to how we have achieved this already with VSAN.

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VMworld 2014 – Storage News Part 1

vmworld-2014-active-banner-v4Yesterday was my first day at VMworld 2014. As usual with this event, there are simply so many interesting announcements that it is hard to keep track. However, for me, there were a few things which stood out in the storage space worth calling out. These are specifically VMware focused products and features. I know that many of our partners have also made announcements in the storage space, but for today I concentrated solely on VMware. There are the two that really caught my attention.

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Thin Provisioning Considerations when formatting volumes in a Guest OS

I had this question recently regarding the best way to format volumes in a Windows 2008 Guest OS, and if there were any considerations with the different formatting types on a volume which resides on a thin provisioned VMDK. Just to be certain that what I was stating was actually true, I set up a small test. Bottom line – use quick format when formatting the volume as a normal format will fill the volume, negating the space-saving associated with thin provisioned volumes.

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VSAN Part 24 – Why is VSAN deploying thick disks?

In this post, we talk about a particular behaviour with using the default (or None) policy with VSAN. I have stated many times in the past that when a VM is deployed on the VSAN datastore, it behaves like it is thinly provisioned unless the capability ‘Object Space Reservation’ (OSR) is specified in the VM Storage Policy. The OSR will pre-allocate space on the VSAN datastore for the virtual machine’s storage objects, and is specified as a percentage of the actual VMDK size. However, there is a slightly different behaviour when the default policy is used. Once again, I was in a conversation with a customer who stated that when he used the default policy of “None”, he could see space being consumed on the VSAN datastore was equal to the size of the VMDK * FTT (Number of Failures To Tolerate). He wondered why this was the case when the default policy clearly did not contain an Object Space Reservation capability.

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