The greatest challenge to any thinker is stating the problem in a way that will allow a solution

Bertrand Russell

Welcome to vBlog, a personal record of my techy tinkerings and particular ponderings.

I tend to focus on VMware virtualisation, and the interaction/automation of it using PowerCLI (VMware's PowerShell Snapin), but anything that I happen to stumble across that seems like it might be of use at a later date, may well get recorded here.

I also maintain vWiki, which was a predecessor to this blog. Wiki's are great for quickly recording snippets of info, but tend not to look that great; Blog's are better looking things, but seem to require more effort so that the posts/articles are accessible in their own right. As a result I tend to update both interchangeably as available time, and depth of thought, permit.

If you happen to find anything of use, or in need of correction please leave a comment. Knowing that my ramblings are of some use is a great reward; and similarly I'd hate to waste anybody's time by feeding them duff info.

See these pages for me info about me, and my vBlog, and below for my recent posts...

The ability to snapshot a VM is wondrous thing; the ability for a snapshot to be forgotten, eat up all all your storage or grow so large that you can’t remove it without causing impact is not so wondrous.

How you manage snapshots is up to, but unless you routinely tidy them up (especially if you use some thing that utilises snapshots like vRanger, which can occasionally leave them behind), they will cause you a problem at some point.  And sod’s law dictates that the problem occurs to important VM, when you haven’t the time to spare. Continue reading →

A while back I came across an intermittent storage problem, whereby paths were occasionally going down and coming back up for a period of time.  In order to be able to tally the timings of the events up with other goings on (eg when looking at SAN logs etc) I needed to create a an export of when the events were occurring.

Note that Get-VIEvent is limited to 1000 results, which will typically get 1 – 2 days worth depending on your infrastructure. To get a longer history would require multiple calls to Get-VIEvent using the -Start and -Finish parameters Continue reading →

Its bizarrely difficult to be able to map VMware presented datastore names to the underlying LUN’s in the PowerCLI, despite the fact that its readily available via the VI Client.  It’s even more difficult if you have to worry about both VI3 and VI4 vSphere installations as they handle storage in differing ways, hence the two different approaches below. The ESX3 method attacks the problem by starting its search at an ESX, whereas for ESX4 we start the attack at the cluster…

Continue reading →

This post covers what you need to do to be able to run an ESXi3 server from a USB stick (if you’re installing ESXi 4 then you don’t need to do this, the VMware installer will detect the USB stick (or SD card) and install to it).

Note that while in theory an ESXi server makes very little use of the storage its running from, there is an important exception.  ESX3 HA will write to the storage, and in HA enabled clusters its possible for USB keys to become worn out.  This typically rears its head when trying to add/remove a server to an HA cluster, and this operation fails.  There are ways around out (not least replacing the USB key) and I’ll probably post on this later in a more general HA problems post.  Note that this problem is limited to ESXi3, ESXi4 HA is much more forgiving to the ESX’s storage.

So why do it? Continue reading →