Heads Up! Device Queue Depth on QLogic HBAs

Posted on April 24, 2013 by Cormac — 15 Comments ↓

Just thought I’d bring to your attention something that has been doing the rounds here at VMware recently, and will be applicable to those of you using QLogic HBAs with ESXi 5.x. The following are the device queue depths you will find when using QLogic HBAs for SAN connectivity:

ESXi 4.1 U2 – 32
ESXi 5.0 GA – 64
ESXi 5.0 U1 – 64
ESXi 5.1 GA – 64

The higher depth of 64 has been this way since 24 Aug 2011 (the 5.0 GA release). The issue is that this has not been documented anywhere. For the majority of users, this is not an area of concern and is probably a benefit. But there are some concerns.

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Adaptive Queueing vs. Storage I/O Control

Posted on January 22, 2013 by Cormac — 8 Comments ↓

This post is to look at two different technologies available in vSphere to manage the queue depth on your ESXi host(s). A queue determines how many outstanding I/Os can be sent to a disk. In the case of vSphere environments, where many hosts can be doing I/O to the same shared disk device, it can be helpful to throttle the LUN queue depth from time to time when congestion arises. In this post, we will compare and contrast Adaptive Queues with Storage I/O Control (SIOC).

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vCenter Server 5.1.0b Released

Posted on January 3, 2013 by Cormac — 3 Comments ↓

This is a follow-up to my previous post on the 5.0U2. At the same time, VMware also released vCenter 5.1.0b. This post will look at the storage items which were addressed in that update, although the issues that are addressed in the storage space are relatively minor compared to the enhancements made in other areas. Note that this update is for vCenter only – there is no ESXi 5.1 update.

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vCenter 5.0U2 & ESXi 5.0U2 Released

Posted on January 2, 2013 by Cormac — 3 Comments ↓

Hi all,

Prior to the holidays, VMware released new versions of vCenter & ESXi on December 20th. There were new releases for both vSphere 5.0 & 5.1. In this post, I want to discuss release 5.0 Update 2. There were a number of notable fixes specific to storage which I wanted to highlight. I will follow-up with a look at storage enhancements in the new 5.1 release in a future post.

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NFS Best Practices – Part 3: Interoperability Considerations

Posted on December 12, 2012 by Cormac — 4 Comments ↓

Welcome to part 3 of the NFS Best Practices series of posts. While part 1 looked at networking and part 2 looked at configuration options, this next post will look at interoperability with vSphere features. We are primarily interested in features which are in some way related to storage, and NFS storage in particular. While many of my regular readers will be well versed in most of these technologies, I’m hoping there will still be some items of interest. Most of the interoperability features are tried and tested with NFS, but I will try to highlight areas that might be cause for additional consideration.

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