Musings of Rodos

As a VMware geek one of the things I am often doing is searching through the Technical Resources Documents which are found at http://www.vmware.com/resources/techresources/cat/91

However it can be very hard to find relevant documents. There is effectively no search function and you have to go into the subpage to read the description.

To work around this I created a searchable document which list all of the technical papers, their descriptions and links. Its on one page so you can simply search it for key words.

The document is VMware Technical Resource documents listing at http://communities.vmware.com/docs/DOC-2590

I hope you find it useful.

I am a big fan of the FireFox browser. The foxmarks extension which syncs your bookmarks across different computers is very handy.

The best thing though is the keywords for bookmarks. If you have a bookmark you go to a lot you can enter a keyword for that bookmark. Instead of typing in a URL you can enter the keyword.

Forget using the mouse to click on the address bar and then type in some long address, simply do a CTRL-L (or CTRL-T if you want a new tab) and then enter your keyword and hit enter. The keyboard is so much faster.

For people like me who are always looking up reference information on the same pages its a great feature.

I really should blog more. Oh well.

Its hard to have a conversation these days without someone trying to convince me that Fiber Channel is dead and iSCSI is where it is at. Whilst I agree with this in the long term I don't see it in the short term. Sure anyone can get iSCSI working in a lab hacking a few free things together, but thats not comparing apples with apples. You need to compare deploying iSCSI in a best practice environment to a FC one.

Here is my current argument, email me if you think I am wrong or have missed something.

• Fiber Channel switch costs. If you only have two hosts, which can be common in a VMware environment, you can get away with no FC switches. Just connect each port of dual dual HBA to each storage processor on you SAN. If you have more than two hosts then you are going to need some FC switches, say $3.5K each. If you are following best practices for your iSCSI you would have a separate switching infrastructure for the storage, these are going to cost you about the same. Let alone what a 10G switch will cost.
  
• HBA cards. Well a dual port HBA card is going to cost you about $2K. Two high end network cards with TOE are going to cost you about $1.6K, thats not a great saving.
• A lot of the arguments are based on 10G Ethernet. People are not already running this so they are going to have to go out and purchase bleeding edge switches and cards compared the now commodity fiber channel equivalents.
  

Now there are lots of other elements to consider but for the big ticket items for the size of installations I see (two to ten servers running VMware) the cost difference is not drop dead argument of iSCSI is so much cheaper than FC.

If it was not for VMware I think FC would be dead a lot sooner than it otherwise would have been, its still got some legs for a while.

Just an update on my old post on OpenFiler.

I wanted to give iSCSI a play and I notices that the OpenFiler people have a prebuilt VMware appliance, sweet.

Downloaded the appliance, created a new virtual disk and presented it via iSCSI. I then install the Microsoft Initiator and connected things up. It was reasonably straight forward. The only two issues I had was you can't configure anything as iSCSI until you setup some networks and the chap authentication caused me grief for quite a while. Lastly there is very little debugging or technical info for OpenFiler, that I could find. However, I did get it running in a short period of time, that was cool.

Having build a few smaller data centers in my time I have an interest in the topic.

Came across a new organisation The Green Grid. They have an interesting white paper on Guidelines for efficient data centers.

There is some interesting info and its very practical. There is the usual stuff like hot and cold aisles and so on. However it does mention some issues which I have seen in the field but you don't hear reported much such as this one.

COORDINATION OF AIR CONDITIONERS
Many datacenters have multiple air conditioners that
actually fight each other. One may actually heat while
another cools and one may dehumidify while another
humidifies. The result is gross waste that may require
a professional assessment to diagnose.