Posts

I’ve been a huge fan of Microsoft Exchange ever since I’ve been involved in managing email servers. Exchange has been a topic of several of my posts this year because let’s face it, Exchange is the 100 lb gorilla of mail servers and has been for some time. But I’ve seen a fair number of colleges using a new mail system from Zimbra so I thought it was my duty to try it out. After all, there is a free 60 day trial of a VMware appliance available so what did I have to lose? ...

This is a series of posts designed to help readers understand how the Internet works. This specific post looks directly at how devices know what machines are on their network segment. In previous posts, we looked at how machines communicate on the same network by utilizing frames, and how machines on different network segments use packets. The next logical question is, “How do machines know if these machines are on the same network or not?” The answer to this question is subnetting. ...

This is a series of posts designed to help readers understand how the Internet works. This specific post looks directly at collision domains. Ethernet uses a process called “Carrier Sense Multiple Access with Collision Detection” or CSMA/CD for short. This is a very long way of explaining the process of how network adapters can share the same media to communicate. Think about it if you have 10 machines on a network that are all sharing the same wires or devices, how can any of the devices understand anything with all those frames? ...

This is a series of posts designed to help readers understand how the Internet works. This specific post looks directly at how machines on different network segments communicate. In my previous post, we looked at how two machines on the same network segment exchange information by using frames. So what happens when two machines on different segments need to communicate? Encapsulation Before we get too involved in the discussion, we should take a peak at what an IP packet looks like. IP Packets relate to Ethernet frames much like one nesting doll relates to the rest in the set. ...

This is a series of posts designed to help readers understand how the Internet works. This specific post looks directly at how machines on the same network segment communicate with each other. We’ll look at the concept of a network segment in a future post, but for now all you need to think about is how two computers communicate on a Local Area Network. MAC Addresses Before we discuss how machines on the same LAN segment communicate, we need to understand what Media Access Control (MAC) addresses are. A MAC address is the physical address of a network adapter. These are 48 bit addresses that are expressed as 12 digit hexadecimal notation and are unique to each network adapter. Each manufacturer has an assigned range that they are to use for their first 24 bits, this is known as the Organizationally Unique Identifier (OUI). The second 24 bits are known as the Network Interface Controller (NIC) specific and must be unique within that vendor’s range. Keeping these ID’s unique is imperative for successful LAN communication. ...

HP announced a new virtual storage appliance (VSA) recently at their annual HP Discover conference. This is a virtual appliance based on the StoreOnce line (formerly known as D2D) of hardware appliances that HP has sold for a long time. These appliances have the catalyst software which allows for deduplication of all your backup data, hence the term StoreOnce. These devices have allowed administrators to switch from the older tape based backups to a virtual tape library (VTL) or a NAS type backup solution. It has replication options in it which allow for deduplicated data to be migrated or copied without re-hydrating the backups and wasting valuable bandwidth. It also allows for federated backups and when matched with HP Data Protector 8 (also newly released) can throttle bandwidth during backup operations in order to prevent production slow downs. ...

I’ve never paid too much attention to the different types of RAM (Random Access Memory) during my tenure as a Systems Engineer but wonder how much time it would have saved me in troubleshooting. This post is not only an attempt to educate other technicians, but an opportunity to refine my own knowledge of the subject. There are three main categories that I want to review. Ecc vs Non-ECC, Unbuffered vs Registered memory, and Memory Rank. ...

I recently purchased a Synology DS411slim NAS device for my home lab in order to quiet down my rack and start using up less power. Obviously to accomplish this I would need to fill it up with Solid State drives which have the added benefit of a large number of IOPS :) I screwed my four 480GB OCZ SSD’s into the drive cages and slipped them into the chassis. Really my only con for this device was getting the drives into the chassis. I did have to do a bit of wiggling to get them seated correctly. ...

This post was a direct result of a request from one of my readers. I hope that this post will explain VMware networks a bit more and how they fit into a production network. To begin I’d like to review how a VMware ESXi server might have its virtual switches and port groups setup to connect to a physical switch. Here is a list of networks that we’ll be working with. ...

I was recently interviewed by Andrew McCaskey from SDR News about the HP Discover conference. The interview is below http://www.youtube.com/watch?feature=player_detailpage&v=IUM-sDiHD18