A change to sub-blocks on VMFS-6

Something that I only just recently noticed is that we have made a change to the sub-blocks structure on VMFS-6, compared to VMFS-5. Sub-blocks are small allocations on a VMFS volume, and they are used to back small files. They were introduced as a space-saving measure to prevent using a full file block to back a very small file. To put this simply, when a [...]

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VAAI Comparison – Block versus NAS

I get a lot of questions around how the vSphere APIs for Array Integration (VAAI) primitives compare from a protocol perspective. For instance, a common question is to [...]

Heads Up! VSA Manager 5.1.x – Install Error 2896: Executing action failed

I was asked recently to provide some assistance with a VSA installation problem. The issue which this person experienced is described in the release notes for VSA 5.1.1 [...]

vCenter Operations Manager – Caught out by new Solution Licensing step

In a few recent posts, I've been looking at performance counters in vSphere 5.1. One of my colleagues, Hugo Strydom, reached out to me about doing a vCenter Operations (vCOps) [...]

Heads Up! If running VSA 5.1, you do not need VSA 5.1.1

Folks, This is currently not very clear in the release notes, but if you are already running vSphere Storage Appliance (VSA) version 5.1, you do not need to update to VSA [...]

Why is the siocActiveTimePercentage counter only ever 0% or 100%?

Last week I published a blog article about new performance counters in vSphere 5.1 for monitoring Storage I/O Control (SIOC). Soon after publishing, I received a question [...]

Atlantis ILIO – Diskless VDI & Services Feature Review

My first introduction to Atlantis ILIO was at a User Group meeting in the UK last year. I had a chat with Jim Moyle who explained the Atlantis ILIO product to me. Their [...]

Monitoring Storage I/O Control activity with new vSphere 5.1 counters

There was an interesting question posted recently around how you could monitor Storage I/O Control activity. Basically, how would one know if SIOC had kicked in and was [...]