VMWare migration

6 09 2010

Migrated a Virtual machine using vConverter from an ESX3.5 host to an ESX4.1 host, and got the following error upon attempting to boot the machine:

CPU min outside valid range

This prevented the machine from booting.

According to the VMWare Knowledge Base, this issue “… occurs when the CPU reservation of a virtual machine is greater than the total CPU available on a single processor.”

Check the CPU reservation settings on the source machine: Right-click on the VM –> Edit settings –> Resources

I did this with my source machine, and saw that the CPU reservation had been configured manually (as opposed to being set to “unlimited”, for example).

To fix, I carried out the migration again (this is a live server, so the data on it is changing constantly – therefore the machine has to be re-copied each time), and manually changed the CPU reservation to an acceptable value.

Job done.





“Network Warrior” book

2 09 2010

Just finished the 500+ page “Network Warrior” by Gary A. Donahue, published by O’ Reilly. This took almost exactly 1 week.. a lot quicker than my average read!

The book was a brief interlude from my current study for the ICND2, which I need to pass to complete my CCNA. The summary on the front cover reads “Everything You Need to Know That Wasn’t on the CCNA Exam”.. so it could be argued that I was perhaps being slightly premature, considering I haven’t actually taken the exam yet!

The main reason for buying this was the reviews on Amazon – so many people had written that it was a vital read for anyone in the networking field that I couldn’t ignore it.

I’d added it to my wishlist and forgotten about it, then saw it there when I added another book to my basket, the CCSA book I wrote about here.

I decided to buy the books together, and when they arrived, two days later (despite paying nearly £10 for next day delivery I might add – cheers Amazon!), I had a quick flick through.

I wasn’t mightily impressed with initial impressions of the CCSA book, but this was a different kettle of fish.. almost straight away I stumbled across a way of filtering the output of the show-mac-address command, which happened to be exactly what I needed to help track down a duplicate IP address on my network flagged by the logging on my Syslog server.

This got me hooked, and the next day, a Saturday (I was pretty flu’d up..), I read for about 5 hours solid. I could barely put the book down! At work each day this week, I spent 40 minutes of my lunch break reading it, and then finished it tonight.

The things that make this a great book are:

  • The real-world experiences that the author writes about, which contain many words of wisdom from an industry veteran
  • The way that a topic is described in one chapter, and then the ways of implementing it are written about in the next.. this gives an understanding of the theory as well as the more practical side
  • The broad range of subjects it covers.. I felt compelled to investigate quite a few subjects in more detail than the book goes in to
  • The style is a departure from the certificaton study guide style of book – it lacks that touch of paranoia about ensuring that all exam topics are covered in intricate detail that some books show (most notably Microsoft Press exam guides – snore!).

I did skip through some chapters, most notably the subnetting one – I have honed my subnetting using a combination of techniques that I’d learned from two CCENT training video series, and wanted to avoid confusing matters.

One thing that I think is vital to mention is the Cisco-centricity of the book. The theory chapters include information which is the main, vendor neutral, but all config examples are Cisco (both IOS and CatOS), and all hardware mentioned is Cisco kit. This wasn’t an issue for me, as someone studying for the CCNA, but it may be for some.

Although this books isn’t specifically aimed at helping you to pass the CCNA (in fact it probably goes in to a lot more depth on certain topics that the CCNA requires), it is incredibly complementary to both this and obtaining more all-round knowledge of the topics covered. A very worthwhile read:

Hands-on: 3/5

Theory: 4/5

Keep my attention: 4/5

TOTAL: 3.5/5





Just brought *a lot* of my network down..

27 08 2010

.. by changing the port mode of a Cisco switch that was connected to a Dell switch to trunk mode from access.. fixed immediately by restoring the port config from backup (gotta love right-click to Paste in Tera Term ha ha).

Restored the port config from backup and everything was working again very quickly.. this is what 19:00 on a Friday (non working hours) is all about! Hehe. Only problem is, not got a serial cable to hand to connect to the Dell switch to try to work out the config there.

Needless to say, I’ve asked for budget for Cisco switches to replace the Dells next year ; )

Full write up in the next few days – I was in the middle of a great “walking the network” session to diagnose a duplicate IP, reported by one of my switches to a Kiwi syslog server I’ve set up at the time.

This is exactly what I started this blog for (well, not specifically to break stuff, but to write about my findings when stuff does break, and show how I fixed it) – amazing ; )

Night!





CCSA book alert

27 08 2010

I’ll interrupt my series of posts about CCENT certification aids to mention a book I’ve just bought related to the Checkpoint Certified Security Administrator exam.. this was slightly premature, as I’ve not long started studying for the ICND2, but I bought it anyway. It’s the book by William Manning, with the tagline “The How to Pass on Your First Try Certification Study Guide”.

I’ve only skimmed the content at the moment, but wanted to point out that this is designed as a complement to a course on the subject, and seems to be written as a refresher of key points, rather than an in-depth learning resource. This wasn’t the impression I got from Amazon, so thought I’d stick a note here. Review on the actual content to come once I’ve read it.