Heads Up! Device Queue Depth on QLogic HBAs

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…

Tintri 2.0 – Per VM Replication Feature

Last week, I had a chance to catch up with Brady Murray and Rex Walters of Tintri. Mostly this was a transfer of information, but the guys let me know that they are on the verge of announcing a new per-VM replication feature which they first demoed to me when I met Tintri at VMworld last year. This will be the main feature in Tintri’s new 2.0 launch.

VMware Mobile Knowledge Portal (VMKP) app version 2.0 is now live!

For those of you who would like to access VMware’s Technical Marketing material whilst on the move, we are pleased to announce version 2.0 of the VMware Mobile Knowledge Portal (VMKP) app is now available. The VMKP contains all Technical Marketing content including Videos, Evaluation Guides, What’s New papers, White Papers & Posters. These pieces of collateral may also be downloaded for offline viewing. This new version now supports Android devices as well as IOS iPad device. Please check out the post by Alan Renouf on the vSphere blog to learn more, see some sample content and the links on…

What are Dependent, Independent Disks & Persistent and Non-persisent Modes?

I had a query about this recently, and actually it is a topic that I have not looked at for some time. Those of you configuring virtual machine disks may have seen references to these different configuration options and may have wondered how they affect the behavior of the virtual machine. Read on to find out the subtleties between Independent Persistent Mode and Independent Non-persistent Mode disks, and what impact they may have.

Heads Up! New Patches for VMFS heap

Many of you in the storage field will be aware of a limitation with the maximum amount of open files on a VMFS volume. It has been discussed extensively, with a blog articles on the vSphere blog by myself, but also articles by such luminaries as Jason Boche and Michael Webster. In a nutshell, ESXi has a limited amount of VMFS heap space by default. While you can increase it from the default to the maximum, there are still some gaps. When you create very many VMDKs on a very large VMFS volume, the double indirect pointer mechanism to address…

Microsoft Clustering on vSphere – Incompatible Device Errors

When setting up a Microsoft Cluster with nodes running in vSphere Virtual Machines across ESXi hosts, I have come across folks who have experienced Incompatible device backing specified for device ‘0’ errors. These are typically a result of the RDM (Raw Device Mapping) setup not being quite right. There can be a couple of reasons for this, as highlighted here. Different SCSI Controller On one occasion, the RDM was mapped to the same SCSI controller as the Guest OS boot disk. Once the RDM was moved to its own unique SCSI controller, it resolved the issue. Basically, if the OS disk…

A closer look at GreenBytes

Followers of my blog will have seen a number of articles posted recently about storage vendors that I managed to catch up with at this year’s VMware Partner Exchange in Las Vegas. In the last in this series of articles, I managed to spend some time with the folks from GreenBytes. The timing was very opportune, as GreenBytes just made a major announcement to their portfolio, namely their new vIO, the virtual storage appliance version of their IO Offload Engine solution for desktop virtualization. I met up with Michael Robinson (VP, Marketing), Jeff Eberhard (Sr. Systems Engineer) and Steve O’Donnell…