Monthly Archives: March 2012

Bug when Updating Virtual Hardware in VMware

English, Technology, Virtualization, VMware, ,

Just realized how fragile a virtual machine can be.

Yesterday I logged into a Windows server and found that some programs were missing (python among others). No big deal. I just assumed that someone else had removed them to free up space or something. Then I found a few files I knew I had both edited and deleted. And the files I knew I had touched suddenly had a timestamp dating back to 2008. Luckily this isn’t a critical production machine, but never the less, how could this happen?

When I checked the vCenter log, I found that the virtual hardware on this particular VM was updated just short of 24 hours earlier. The VM also contained a system generated snapshot dated 2008. The Windows event log, however, where having a gap from 2010 till 2012 (current day).

What has happened is this:

• The VM was powered off.
• The virtual hardware was upgraded.
• When the machine was turned back on, the system reverted back to a previous snapshot (without logging it), thus overwriting the current image.

There are several things here that I find “scary”. The first is that the VM went back using an older system state without even logging it.

The second “scary” thing is that the system generated snapshot was wrongly labeled with the year 2008, when it clearly contained data from 2010 (We actually tested this by reverting to this image just to check. We had nothing to loose anyway).

Lenovo ThinkPad T520 and Sound Issues

English, Technology, , ,

Since I received my Lenovo ThinkPad T520, I’ve been experiencing some really bad audio. Playing video at the same time only made it worse, at least that was my initial impression. The problem mainly consisted of crack and pops in the speaker. I downloaded a small tool called DCP Latency Checker, and discovered that the problem was due to high latency every now and then. I’m talking about latency in the 90000+ µs range.

For the record; I’m using Windows 7 (64-bit) with Service Pack 1.ThinkPad T520

To make a long story short. I search the internet, and found various answers. My first break through was when I disabled the network card, the wired one. The second came from a friend of mine.

So what I ended up doing, in this order, was downgrade the network driver, since the newest driver wasn’t working properly (duh). Searching for Intel 82579LM eventually led me to HPs website. I’ve tried two or three versions from Lenovo’s site, and two other directly from Intel, with only minor improvements. Turns out that the old driver from HP (SP52209.exe), dated 2010, is the best driver I’ve tested so far. Also, I disabled the ATA Channel 3, and eventually Channel 4 as well. I did try the newest network driver with the two ATA Channels disabled, but the problem reappeared.

Device Manager

So there you have it, my solution to the problem, disable a couple of ATA Channels and downgrade the network driver to an old version fresh from HP.com.