We Got Served

Last month, I wrote an article about a new application for WHS called Drive Balancer.  That article was based off the original released version of this application.  A few iterations has occurred since and it is time to do a formal review of the program.

What is Drive Balancer?  This program was written to provide an automated method to evenly distribute your data across your WHS pooled hard drives.

Drive Balancer comes packaged in a zip file containing the executable and two readme files.  Create a folder where desired and unzip the files to that destination.  There have been some discussions regarding the location of that folder in this thread, but I chose to place it on my D: (pooled) drive.  Better to have me as the Guinea Pig than you, right?

One “feature” you will notice about this program is that not is not a WHS add-in in the normal sense.  It does not integrate into the WHS Console.  It is a command-line executable program.  You can start and use this program from within the WHS Console through an appropriate add-in, such as Advanced Admin Console.  But it is not a Console add-in.  It might be nice if the author could rewrite the code to make this an add-in application, but it is certainly not a requirement.

Enough of the “wish list”.   Back to the program.

As you can see in the following picture, my distribution of files is currently not the greatest.  At some point between my previous article and this review, I must have removed a drive, added it back, added stuff, removed stuff, etc.  My WHS is never a stable production machine.  I really need a decent WHS test bed!

Back to the distribution of files.  Is that distribution good?  Is it bad?  I don’t really know, but I do not think it is bad.  Symmetry, however, seems to be a normal human condition.  It just looks better (nicer?) to have that data spread evenly.  Which is where Drive Balancer comes in.  Before you run this program, be sure to read the included readme file, and the walk_through file, documented below for your perusal.

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How to Install:

Download the zip file and put it on a share on the WHS machine. Now, RDP into the WHS machine as Administrator and unzip the exe onto the C: drive. I’ve always run it on a share, but I’m not sure that won’t lead to a problem, so running from C: is definitely fine. Now, you can either just double click the exe or you can open a cmd window and run it from that. I also suggest keeping the Disk Management tab open in WHS console so you can see the drive activity if you so choose.

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Before Running, I suggest…

1) Stop all clients from writing data to the pool while the app is running. Writing to the disks will mess up the calculations from even distribution and if you write too much, you’ll end up seeing no progress in the final step after some time and you’ll have to let the timeout expire (30 min of no progress).

2) Stop clients from reading data while the app is running. Not nearly as important, but I say this here because you’re read performance to a client is going to be horrible if the app is moving data on the disk your client is reading from.

3) Stop SageTV service or any other service on the WHS machine which affects #1 and #2. Some users have reported crashes of the tool (again not a big deal, but you’ll manuall have to cleanup the d:fake and c:fs*fake directories.

4) Basically, you ideally want an idle server (minus your RDP session) for best results. Not listening to these suggestions will not break anything other than the efficiency of the app, so no harm will occur to your data.

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Things that can cause a less than stellar results

1) Look at the amount of Shadows as a whole on the drive pool. If this number is greater that 0, it will affect the final outcome of drive balance. I found that I had 100GB+ of Shadows during my first run of drive balancer. After the first run completed, an overnight run, the shadows were gone. I then reran drive balancer and it finished up the job.

2) The amount of duplicated folders can may make it difficult to get a “perfect” balance. I am not suggesting turning off duplication on anything, I’m just pointing out that duplication will limit the choices DE has when it moves around files. If you have 4+ disks in the pool, this becomes less of an issue since DE will have more choices.

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Here’s a typical walk through of the program’s steps

1) Decide if you want to include D: in the balancing effort. This is a personal choice, so I’m just giving the option. Personally, I’m not sure what’s better.

2) If you chose yes to #1, then skip to number #4. Otherwise, the D: is now filled up with fake files to within 10GB of it’s capacity. You are then asked if you want to clear data off of the Landing Zone. Again, personal choice, so you decide. I just put in the options.

3) If you chose no to clearing the landing zone, skip to #4. Otherwise, The app will restart DE and it should start to move off data. It will do it’s best to move off data, but if after 30 minutes of no progress, it will declare victory and move on.

4) Time to choose how you want to balance the data and make a few calculations. They are self explanatory, so I won’t dive into that. There are checks in there to make sure you don’t try to overfill a drive or don’t have enough capacity. Remember, this tool doesn’t delete/move/copy your data files, it just creates fake files to get DE to do what we want. After the calculations are made, you will be asked if they seem appropriate. If you say no, the app cleans up and exits. If you say yes, move on to #5.

5) Now it’s time to balance the data. Suffice to say that It will tell how it progresses, when it goes to sleep, and when it tries to restart DE. If you find it isn’t making progress, you can hit Ctrl-C. You must then delete the D:fake and C:fs*fake directories to cleanup.

I have found that if you aren’t happy with the balancing results another run can help. The issue is I’m being cautious in balancing the data and it’s sometimes too cautious to get good results. The perceived “cautiousness level” is indirectly proportional to the amount of data in your pool. The more data, the perceived cautiousness is lower. The tool is more aggressive than past revisions, and should be within 10-20GB on each drive.

At this point, simply fire-up the executable.  Follow the instructions, sit back and relax because it takes awhile to move data around.  The first question that will be asked (as indicated in the author’s walk-through file) is whether you want to include D: in the balancing effort.  Just so you understand what this is, this is the extended partition of the System drive (sometimes called the “Landing Zone”).

As can be seen in the following picture, I chose to not use this physical drive partition in this effort.  It really wasn’t necessary, as it this had been done previously, but I simply wanted to go through the process again.

Just some more Landing Zone questions, which asks you if you wish to move existing files off the extended partition.

In this case, I indicated that I did want to do so.

And Drive Balancer goes to work.

During this time, you will notice that the Home Network Health icon goes red:

Perfectly normal and it will return to a normal state.  Once Drive Balancer has done it’s work.  The following pictures just indicates the moving and completion of movement of files off the Landing Zone.

Finally, one is ready to tell Drive Balancer how you want it to balance the data.  You will notice 4 options, plus the Quit option.  In my case, I chose 1: the equal percentage option.

It does a quick calculation and asks to proceed.

And finally, it is time to do the the real work.

At this point I went away and sometime later, I opened my RDC and watched as the program command-line window closed as the RDC opened.  It had done it’s balancing, as can be seen below, but it seemed to exit prematurely, as the “fake” data was still on the Landing Zone.

It was no big deal, as I simply deleted those files.  The result:

A few minutes later, the red Home Network Health icon became green and I was done.  Symmetry is bliss!  Well not quite.  It used to be important to have adequate space on this Landing Zone, as WHS put files there first prior to moving them to other physical drives.  This procedure has changed, and it is no longer as important.  As such, there seemed to be quite a bit of waste (and lack of symmetry!) of drive space.  So I ran Drive Balancer one more time and kept the Landing Zone as part of the balancing effort:

The result:

Once Drive Balancer completed its task, the command-line window closed once again without user input.  Whether this is designed to be this way or not, it makes me somewhat uncertain of whether the application finished its tasks and closed or simply closed due to some error.  The as-finished pictures indicate that the tasks were completed as requested (The big red storage line seems to be a WHS Disk Management bug).  In the first run, it would seem to not be the case, as the fake files were still there.  Perhaps I did not wait long enough for some background task to delete them?  I rather doubt this but who knows, as the application simply closed the command-line window on it’s own.

Which is at this time the only real gripe I have.  Once the tasks are completed, let me close the command-line window.  That way I am certain the the application has finished.  It would be nice if it could do a final error check on the to-do tasks to see if everything completed, and document that list in the window.

Author: Beefcake

Version Reviewed: 1.04

Release: 18Mar2009

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