UK Floods 2014

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Here are a few of the photos I took in Reading town center of the river Kennet during the period of flooding we had in the UK during spring 2014. Although Reading wasn't too badly affected, it was quite surreal to see the river this high.

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A few more photos can be found on my Flickr account here.


Making FC Zone Changes on Nexus 5500 Series

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I am fairly new to the world of FibreChannel, and recently discovered a gotcha when making changes to zoning configuration for one or more zones which are part of the active zoneset, which I will share with you now.

A Cisco Nexus 5548UP (Unified Ports)

Updating the zone configuration

Below is a sample zone configuration for a Nexus switch, and we can see that we have two WWN’s in a zone, the zone is part of a zoneset, and that that zoneset has been activated.

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zone name MY_ZONE_NAME vsan 101
    member pwwn xx:xx:xx:xx:xx:xx:xx:xx
    member pwwn yy:yy:yy:yy:yy:yy:yy:yy

zoneset name MY_ZONESET_NAME vsan 101
    member MY_ZONE_NAME

zoneset activate name MY_ZONESET_NAME vsan 101

Now, suppose that you make a change to that zone, or add another zone to the same zoneset; although the zoneset is already ‘active’, your changes wont be applied.

In order for our changes to be applied, we must re-activate the zoneset which, at first glance sounds like a disruptive operation. The zoneset activate command is part of the running configuration, and to disable and re-apply such config items we typically negate the command (no zoneset activate…) first and then re-apply it.

In this situation simply re-issuing the same command which is already in your running configuration will update the active zoneset in a non disruptive fashion. In my case I needed to configure zoning for a new server (Running ESXi) which needed access to VMWare datastores on the SAN.

I hope this helps somebody out as although I thought it must be possible to add new zones without causing downtime it was unclear at first.

-Aaron


Octopress

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Welcome to my new blog, I thought that I'd give Octopress a try, as it seems like a very interesting and efficient way of creating a blog. All the pages are static, and posts are written in Markdown; Octopress itself is a ruby application, and a simple rake task is used to create new posts or update the static files.

I'll be migrating some things over to the new site soon, in the mean time here is a picture I took at the London Olympics last year of the ArcelorMittal Orbit sculpture thingy…

octopress


Strange .tooltip() error with jQuery UI

Whilst developing for my final year project today I encountered a very strange 'bug' using a tooltip in jQuery UI. I was calling the tooltip method on the whole document model upon page load, like so:

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$(document).tooltip({ track: true });

…which had worked completely fine in the past (It is valid - verified here), but something must have changed in my page because now, upon hovering over an element with a title attribute, the page would go completely blank! <!– more –> I refreshed the page and this time had Chrome's inspector panel open, and actually what was happening was an almost empty HTML document was being loaded:

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<html>
<head><style type="text/css"></style>
</head>
<body></body>
</html>

This bedazzled me as it does not seem like behavior that tooltip should show even if it went badly wrong somewhere; I eventually fixed this by moving my tooltip line to just after my AJAX content loaded and running it on a single

element instead.

If anybody has seen this error or anything similar I would be very interested to hear about it, as I am no expert at web development, and completely clueless at the moment as to why it stopped working, or why my changes fixed it!


Using VNC in VMWare ESXi 5.0

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VNC can be enabled on ESXi hosts to enable remote console connections to virtual machines; this is useful for Mac users who do not have a native VMWare vSphere client or to provide console access for users who are otherwise without the vSphere client.

Verify Host Firewall Settings

The VMWare host needs a custom firewall rule to allow VNC connections, to verify if this already exists browse to the host in the inventory, go to the configuration tab, and click 'Security Profile' under the Software section of links:

using-vnc-in-vmware-esxi-5-0

You should see the VNC firewall rule shown above, if not then the rule needs to be configured: (If the rule already exists, skip to 'Configure a Virtual Machine for VNC' section.)

Read on →

Lady bird

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Taken with my EOS 450d, the kit/stock lens and some macro extension tubes on a bright sunny day in Somerset.

lady-bird