Linux Bonding Modes

When bonding Ethernet channels in Linux there are several modes that can be chosen that affect the way in which the bonding will occur. These modes are enumerated from zero to six. Let’s look briefly at each and see how they differ. Remember that when looking at these modes that bonding can include two or more Ethernet channels. It is not limited to just two.

The mode is set view the modprobe command or, more commonly, is simply inserted into the /etc/modprobe.conf (or /etc/modules.conf) configuration file so that it is configured every time that the Linux Bonding Driver is initialized.

Mode 0: Round Robin.  Transmissions are load balanced by sending from available interfaces sequentially packet by packet.  Transmissions only are load balanced.  Provides load balancing and fault tolerance.

Mode 1: Active-Backup. This is the simplest mode of operation for bonding. Only one Ethernet slave is active at any one time. When the active connection fails another slave is chosen to take over as the active slave and the MAC address is transferred to that connection. The switch will effectively view this the same as if the host was disconnected from one port and then connected to another port. This mode provides fault tolerance but does not provide any increase in performance.

Mode 2: Balanced XOR. This is a simple form of load balancing using the XOR of the MAC addresses of the host and the destination. It works in general fairly well but always sends the packets through the same channel when sending to the same destination. This means that it is relatively effective when communicating with a large number of different remote hosts but loses effectiveness as the number decreases becoming worthless as the value becomes one. This mode provides fault tolerance and some load balancing.

Mode 3: Broadcast. This mode simply uses all channels to mirror all transmissions. It does not provide any load balancing but is for fault tolerance only.

Mode 4: IEEE 803.ad Dynamic Link Aggregation. This mode provides fault tolerance as well as load balancing. It is highly effective but requires configuration changes on the switch and the switch must support 802.3ad Link Aggregation.

Mode 5: Adaptive Transmit Load Balancing. This mode provides fault tolerance and transmit (out going) load balancing. It provides no receiving load balancing.  This mode does not require any configuration on the switch.  Ethtool support is required in the network adapter (NIC) driver.

Mode 6: Adaptive Load Balancing.  Like mode five but provides fault tolerance and bidirectional load balancing.  The transmit load balancing is identical but receipt load balancing is accomplished by ARP trickery.

January 21, 2007: MLK Does a Body Good

Today is Martin Luther King Jr. Day and that means that the markets are closed and I don’t have to go to work.  Yay!  Dominica does not have the day off, though, so it is only a holiday for me and Oreo.  Oreo wishes that he could go to daycare, though, because he has way too much energy and wishes that he had an opportunity to burn some of it off.

When Dominica got ready to go to work this morning Oreo jumped out of bed and tried to go with her.  But she told him to go back to bed and to snuggle with me so he did, reluctantly.

I took my “day off” seriously and did pretty much nothing.  Over the weekend my Ruby script doing the massive migration of Netgear firewall log data from IMAP based email to a MySQL database finally wrapped up at around one million one hundred thousand rows of data.  There is still more being generated every day and I have a bit of old, archived data that I need to figure out how to move as well.  But I have made a good start on it at least.  My email mail box has gone from 195MB to 17MB.

I got to play some Bard’s Tale today but not as much as you might have guessed.  I read some magazines.  Did a tiny bit of cleaning.  Hung out with Oreo quite a bit.  He was very needy today as far as attention went.  He isn’t tired at all and even when he was laying around today he was almost never sleeping.

I tried to have lunch with Susan  and Kevin today but Susan got stuck in a meeting and Kevin didn’t wake up until after two in the afternoon.  So I just had lunch alone at Food for Life.

Dominica got home early and I had to spend my evening taking a midterm exam for my class on project management.  I had to wait for Dominica to get home so that she could handle incoming phone calls (there were two) and deal with the needs of the dog (he ended up needing to be walked again, fed twice, played with once or twice and more just during the test even though I had walked him just before starting it.)  Dominica got home around five thirty and I started the test, all loaded up with caffeine, at almost exactly six o’clock.  The test was to run up to three hours to answer six questions.  So this was to be the majority of my evening.

One topic that we have discussed at length in my project management class and that has come up on this exam (I can mention this now as the exam closed at midnight) is the topic of Measurable Organizational Value.  I decided that I wanted to seriously address the concept of MOV as the book that we are using as our class textbook is based around it and research online seems to suggest that the term only exists for this class even though it is taught as if it was a standard industry concept.  I think that MOV is an important “academia” mistake made by managers who learn management from a book and never work in an actual business and I think that the author really leads people astray.  So I decided to post online my overview of Measurable Organization Value.  It took less than five hours from the time that I posted it until I was on the front page of Google as a top hit for the term and the very top hit for anything less than a three word definition or a link to a review or place to buy the book with that title.

About two hours into the test Oreo got very upset that I was unable to spend time with him.  He kept trying to talk to me but I kept deferring him to Dominica.  He was very upset and didn’t know how to tell us what he needed and he ended up going into a panic and having an accident that involved peeing not just on the floor but onto my chair that I was sitting in while taking the test.  It was obvious that he was really scared.

So I had to take time out of my test to deal with that cleanup!  What a mess.  Poor little Oreo.  He had a really rough night.  I had to take him for yet another walk immediately after finishing my test as well.

After wrapping up my test Dominica, Oreo and I just watched a few episodes of the first season of <em>The Fresh Prince of Bell Air</em>.  I haven’t seen that show in a very long time.

Back to work tomorrow.

January 20, 2008: This Sunday Sunday Sunday

We slept in a little this morning but couldn’t sleep much as we have the weekend Dungeons and Dragons group getting back together at eleven this morning. We got up and did a little light cleaning and the apartment was still a disaster. We didn’t get it clean but we corrected the worst of the mess.

Ramona was over first. We couldn’t find Kevin and Pam for a while so Ramona and I walked down the stairs to go find them. It was the first time that I have taken the stairs in our building ever. I have never even seen the stairwells. Not that they are exciting or anything. It was a weird feeling, though, to walk all of the way to their apartment. It really helps you realize just how close we all live to each other. It really is just a matter of being several dozen feet away.

Today’s D&D session wasn’t very long. Just two to three hours. Kevin hardly got to actually play any of it because his character, David the Gnome (a bard), got knocked unconscious within the first few minutes and didn’t get revived until the last moment of the our session for the day.

At five thirty I walked over to the NorCrown Bank building and met Susan to help her move some furniture.  The big item was a heavy, old filing cabinet.  That proved to be a bit of work.  While I was there I got a tour of the new New Jersey Symphony Orchestra offices that are now located in the NorCrown Bank building right across the PSE&G Square from our apartment.  They have a nice new office space over there.

The real challenge was moving the filing cabinet up the three flights of very tight stairs from the street to Susan’s top floor apartment in Harrison.  That took quite a bit of work.  But we managed to do it without hitting the walls even once.  That was quite the accomplishment.

We drove back to Newark and picked up Dominica and then drove down to the Seabra Rodizio on Route 21 just north of Raymond.  It is a Spanish restaurant that we have been interested in trying for quite some time but never think of when we are actually looking for a place to go.

Dinner was good.  I ordered a casserole with seafood that I thought would be safe but ended up having a disgusting half lobster in it (an entire lobster just sawed in half) which was incredibly disturbing and almost made the food inedible.  Susan was nice enough to pull most of the meat out of the lobster for me as I just couldn’t eat the meat and have gone inside a dead lobster.  I need to remember that Spanish restaurants are not places where I can even consider getting any type of fish or seafood.  If it isn’t pure vegetarian then it is out of the question.  But all of the food was really good.

We came home and just relaxed.  It was pretty late by the time that we got home and Dominica has to go to work tomorrow.  Oreo got scared while we were gone, it being much later than our usual dinner time, and he had an accident in the hallway so we had to deal with that too.  The night was very short and Dominica pretty much went straight to bed.

January 19, 2008: A Day of D&D

We didn’t get to bed last night as early as we had hoped that we would. It wasn’t actually until after midnight but we just relaxed all evening and I definitely feel better having the biggest chunk of my homework done for the week and not having most of it hanging over my head this weekend when there are other things to do. And my main characters are up to level eight in the Bard’s Tale now too.

This morning I slept in until almost nine thirty. Our bedroom was quite a bit colder than usual and my joints were aching. Oh the joys of getting older. It was just forty-nine degrees in our bedroom when I checked the digital thermometer. We have a temperature clock in the living room. It has the atomic time as well as the temperature where it is located (middle of the living space) and a remote sensor in our bedroom. Very handy as those are the only two real separate zones of the house. The rest of the apartment was a comfortable seventy-two degrees. So I left the bedroom door open hoping that the warm air would spill in for Dominica.

Min got up around ten and set right to work cleaning around the apartment. There is a lot to be done today before people start arriving around one in the afternoon. At a quarter till eleven I ran over to Airlie Cafe and grabbed us a late breakfast.

After breakfast we cleaned together and got ready for everyone to come over.  Ramona arrived around one and Kevin and Pam arrived around two.  This will be Pam’s first time playing Dungeons & Dragons ever although her brother has played for a long time.

We played a good long day of D&D going from two until almost ten when we broke for about forty-five minutes so that everyone could run away and take care of a few things.  Then around eleven or a little before we got back together and played again until close to one in the morning.  The game is moving along a lot faster now that we are starting to get a hang of the rules and of playing together.  Having so many new players and playing with a new set of rules significantly different from the ones that we are used to has made it a lot tougher for the game to flow along.

When we broke for the evening everyone decided to try to get back together first thing tomorrow (read: around eleven) to continue playing for a little while.  Everyone has other things going on tomorrow too but there is a slot in the middle of the day when we can all get back together so we are going to try for that.

Overview of Measurable Organizational Value (MOV)

Measurable Organizational Value or MOV is a term coined by Jack Marchewka as an alternative tool to the more popular Return on Investment or ROI concept which has become a buzzword within the industry over the last ten years and has existed for many more. Marchewka defines measurable organizational value as being “the project’s overall goal and measure of success.”

Marchewka further breaks down the term MOV and says that it must implicitly include the following: be measurable, provide value to the organization, be agreed upon and be verifiable. Let’s look at each of these.

Measurability is obvious yet extremely difficult. Many benefits of IT projects are “soft” and inherently unmeasurable. For example, a project that makes employees more happy cannot be measured as it is never possible to determine how much happiness is the result of any one project and how much other organizational efficiencies can be attributed to employee happiness and morale. And yet we almost all agree that happy employees work better, are more loyal, cost less and interact better with each other.

The idea behind measurability is that no project decisions should be made without a consideration towards how they will affect the project’s MOV. If a new feature is being considered, for example, then that feature should be compared against the MOV. If the feature will not increase the MOV then it should not be included. A relatively straightforward concept, but it basically states that only measurable value should be considered. This is not always intuitive.

Project Management by MOV should provide value to the organization. This is the underpinning of the MOV concept and is analogous to the concept of ROI. ROI, however, is a measurement of the difference between expenditure and the expect value to the organization. MOV does not seem to take into account the cost of its own provisioning and only looks and the measurable business value after project completion while ROI takes into account the cost of providing the MOV as well as having the potential to consider the non-measurable organizational value which may be the driving force or a project.

A project MOV must be agreed upon. Marchewka states that all project stakeholders should agree upon the MOV of a project before the project starts. This requirement includes making business stakeholders as well as technology stakeholders, such as analysts and developers, agree to the MOV before a project begins as a later measurement of project success. This is a difficult task as it is in one group of stakeholders’ interest to make the MOV high while it is in the interest of the technology stakeholders to make it low. This is especially difficult as it benefits the business side to trick or take advantage of the lack of business acumen from the technology side and requires the technologist to allow themselves to be judges of something that they neither understand nor ultimately control.

Verifiability of the MOV is key. Since the project’s MOV is measurable by definition it must then be verifiable. After the project has been completed the MOV is to be verified to determine if the project was successful or if it was not. However, Marchewka does not seem to address the issues of ongoing organizational value. A typical IT project will deliver negative value up front and will increase in value over time and then, eventually, decrease in value until it is replaced. True MOV would not be verifiable until the end of its lifespan.

For example, since code from IBM’s System/360 project from 1964 is still widely in use one would assume that IBM has not yet been able to determine the final MOV for that project. If their initial estimates had been extremely accurate and had taken into account a lifespan that might even top fifty years then the MOV would not yet be able to be verified as having quite reached its full value. Therefore a useful MOV is one that takes into account an acceptable lifespan of measurement but this introduces many more factors.