After some investigation I realised that when VCB performed a dump of the VMDK it was correctly dumping the used space. It then dawned on me that when Windows was deleting files from the disk it was actually only deleting the 'pointer' to the data and not the data itself. When VCB was dumping the VMDK it was correctly dumping all blocks of the disk that contained data. I then started looking for a way to clean blocks that were no longer being used but still contained remnants from deleted files. I found a tool called SDelete that writes zero's where the disk contains free space as seen by the Operating System.

I incorporated SDelete into a basic script that also uses Defrag (the Windows utility for defragmenting disks) to tidy up volumes and potentially reduce the size of backups when using VCB.

The script first enumerates all local drives on the VM. For each drive that Windows deems as being a local disk the script then defragments the volume and uses SDelete to zero any free space that the disk may have. The script is written in KiXtart.

Here is the script:

;=====================================================
;=====================================================
;
; ENUMERATE LOCAL DRIVES - DEFRAG & ZERO EMPTY BLOCKS
;
;=====================================================
;=====================================================

;=====================Accept EULA=====================
WriteValue("HKCU\Software\Sysinternals\SDelete", "EulaAccepted", "1", "REG_DWORD")

$Drives = GetObject("winmgmts:").ExecQuery("select Name,DriveType from Win32_LogicalDisk")

For Each $Drive in $Drives

If $Drive.DriveType = 3

SHELL "%comspec% /c " + chr(34) + "defrag.exe " + $Drive.name + " -f" + chr(34)
SHELL "%comspec% /c " + chr(34) + "sdelete.exe -c " + $Drive.name + chr(34)

EndIf

Next

;=====================================================

I use this by placing the folder CleanDisk (download link below) in C:\Program Files. I create a Windows scheduled task to run either KIX32.exe or WKIX32.exe on say a monthly basis.

NOTE: If you have multiple VMs with VMDKs residing on the same physical storage you will probably want to consider staggering the schedules to reduce I/O on the physical disks.

Download the script and necessary files - HERE

One of the new features of vSphere is the ability to resize disks without having to shut down the Virtual Machine. This was previously impossible in VI3. This greatly speeds up the resizing process which can be executed in a couple of stages:

1) Use the vSphere Client to edit the settings of the Virtual Machine in question. Select the hard disk and modify it's provisioned size as appropriate. Click OK to apply these changes - resizing the .vmdk file.

2) Verify that the .vmdk has been resized by opening the Management Console -> Disk Management to find the unallocated space on the disk that resides in the .vmdk (distinguished by the black colour in the legend at the bottom.) In this case you can see I have increased the size by 5GB.

Right click on the disk (in this case 'Disk 0') and select properties. On the Volumes tab make a note of the unallocated space, in my case it is 5122MB.

Download Dell's EXTPART and extract it on the server that contains the disk you want to resize. Navigate to c:\dell\ExtPart (the default extracted location) and run extpart.exe. When prompted enter the the Windows drive letter of the disk on the Virtual Machine e.g. c:. When prompted for the size to extend the partition by enter the number noted down earlier (I used 5122 in this example.) After doing so the disk should be resized. You can check this by opening the Management Console -> Disk Management and verifying the size of the partition.

NB - If you receive the following error:

"Unable to connect to c: or it does not exist"

There are a couple of workarounds that you could try.

1) Close the Management Console (if it is open) and try extpart.exe again.

2) Try restarting the VM in safe mode and then run extpart.exe. This is not ideal but it is still easier than other methods I have tried to resize .vmdk files.

Booting from the disc revealed it was unrecognised so I burned another - same issue. Burning the same .ISO from a different computer worked so I was sure there wasn’t an issue with the image. I began to suspect a faulty DVDRW drive but even after swapping it any CDs burned remained unrecognisable, even to the drive they were burned in. I tried one of the laptops that came preinstalled with the Dell Windows XP configuration and sure enough it was bootable. I then assumed there was an issue with a driver or some software on the laptop that was preventing the laptop from burning the CD successfully. A peek in device manager revealed no issues with the DVDRW device (mine was a TSSTcorp DVD+-RW TS-U633A). I checked both Dell and Intel’s websites for newer drivers but I already had the latest.

The only application I didn’t have installed was the Intel Matrix Storage Manager, a program used to monitor disks/drives and report their status and/or RAID condition. It seemed pretty far fetched but as the DVDRW drives were SATA300 I decided to install the application. After installing it and burning yet another Knoppix CD I was astounded to see that when I put it into another computer I could successfully boot from it! After testing this on another of the laptops I was sure that it was the lack of the Intel Matrix Storage Manager that was causing the CD burn to fail each time. One thing I only noticed afterwards, when initially using MagicISO to burn the .ISO image (pre the installation of the Intel Matrix Storage Manager) the application never reported it was attempting to 'Close the Session'. Since installing the Intel Matrix Storage Manager I have not had any further issues burning audio or data to CD or DVD.

The latest Intel Matrix Storage Manager is available direct from Intel - Here

A quick dig around on Google afterwards revealed similar issues for Dell owners of Latitude E6400 and E6500 series laptops. It now seems this issue is commonly found on most laptops with the same SATA DVDRW drive as above.

STP was designed to prevent loops from forming in a switch network by identifying and blocking redundant paths. The protocol is also intelligent enough to restore an alternate path when a primary link goes down, thus eliminating downtime. But, whilst the pro's of STP sound good it does have some detrimental effects. STP (unlike RSTP) can take a while to learn about a new device or topology change. As a result, before allowing a new device to communicate (be it a computer or another switch) it first attempts to discover more about it. It is the time delay during this process that can cause problems.

The organisation I work for currently consists of 60 users and of those there are never really more than 3/4 of them in the office at any one time. The chances of someone looping a switch here are even more negligible because every 'floor box' under the desk of all users only has 1 of the 3 network ports patched to a switch (one is used for telephone and the other is unused).

A couple of problems STP was causing me include:

- The failure of logon and/or startup scripts to execute as computers were taking an age to acquire an IP and so could not contact a server
- Clients would timeout acquiring an IP during PXE boot when using RIS

So after deciding that STP had to be disabled I was kind of stumped at trying to find a way to do it! I have disabled/changed STP many times usually through a web interface or using the 'no spanning-tree (vlan id)' command.

There are a few configurable options for STP. One is to enable or disable edgeport mode, the other is the use of a BPDU filter.

Edgeport mode:

When connecting a device to a switch that has a physical network port configured with edgeport mode enabled then STP automatically ignores the learning part of its initialisation. Instead it engages its forwarding state which only usually occurs after the lengthy delay of inspecting a device or topology change.

BPDU filter:

BPDU or Bridge Protocol Data Units are packets of data that contain information on ports, addresses, priorities and costs and are passed between switches to prevent loops in a network. If a loop is detected then one of the switches usually puts the offending physical port into a blocked/disabled state (and BPDUs are sent to make the other devices aware). If the physical path around the network is severed and a backup exists then the blocked port on the backup path is put into the forwarding state offering redundancy. BPDU filtering allows you to prevent a physical port from sending and receiving BPDUs.

It seemed that by forcing edgeport mode on all ports on each switch and by turning on the BPDU filter to ignore all BPDU traffic I could therefore disable spanning tree.

After logging into each Adtran 1524st switch using SSH I first enabled the privileged commandset by issuing the 'enable' command. I could then enter configuration mode by issuing the 'configure' command. I now had the following prompt:

Switch(config)#

I selected all ports on the switch using the following 'range' command:

interface range gigabit-eth 0/1-24

This was the new prompt showing me I am applying configuration to all ports:

Switch(config-giga-eth 0/1-24)#

To enable the BPDU filtering I used the following:

spanning-tree bpdufilter enable

And finally to enable edgeport mode I issued the last command:

spanning-tree edgeport

All physical ports on the switch now had the BPDU filter enabled and had edgeport mode turned on. The switch was now as good as being free of STP!

This procedure is intended to help you in either of the following situations:

1. When you want to move a hard disk from one computer to another where the new computer has completely different hardware to the old computer that the hard disk was in originally (and you still want to boot from it thus retaining your windows installation and all applications/programs).

2. When you want to upgrade the motherboard in your computer without having to reinstall Windows and all your applications/programs. This will only work if the motherboard is still functioning, if it is not then you will not be able to boot the original computer to make the necessary change(s) required for the disk to function with the new motherboard.

To achieve this use the following steps:

Boot the first (old) computer with the hard disk in it as normal, then go to control panel, double click the system icon, go to hardware tab, and click device manager button.

Within device manager find the 'IDE ATA/ATAPI CONTROLLERS' and expand the tab. Right click the controller that bears the name of the chipset present on your mainboard (do not touch the 'Primary IDE Controller' or 'Secondary IDE Controller') and select 'Update Driver'. Select 'No not this time' when it asks if you would like windows update to search for a new driver and click next. Then choose the option to 'Install from a list or specific location (Advanced)' and click next again. Now choose the 'don't search I will choose the driver to install' option and click next. Highlight/select the Standard Dual Channel PCI IDE Controller and again click next. The Standard controller driver will now install, click 'Finish' to continue. Now reboot (click yes when prompted with 'Do you want to restart your computer now?') and logon to your computer as normal. The standard IDE controller driver is now completely installed.

After installing the hard disk in the new computer or installing your new mainboard and booting from the hard drive for the first time you will have to wait a couple of minutes before you can use the computer. This is because Windows is automatically detecting the new hardware and installing all of the relevant drivers it can. Most of the drivers are installed for you automatically. When Windows has finished updating your drivers it will ask you to restart the computer again. Once restarted launch device manager to see which items of hardware still require drivers. You will have to go to the relevant manufacturer’s website to download and install any that are missing.

The reason for me doing this is that the router my ISP provides is absolutely dreadful, when I got it out of the box the firewall was disabled and there was no password to login to the admin web interface. The navigation through the interface when configuring the device is terrible. So you can see why I wanted to change it for something different.

Of the many different vendors’ I have tried in my time, I’m quite a big fan of Netgear products. I’d heard from a friend that the Netgear DG834GT that Sky supplies have custom firmware on them, and that they are locked down to prevent use with another ISP. Still, firmware can be changed cant it?! So I nabbed myself a bargain and purchased a Sky branded DG834GT from eBay for £30. After a quick Google it turns out that Netgear provide a utility for rewriting the firmware to the eeprom in the event of a user bricking their device when upgrading it through the web interface. I was also going to need the original Netgear firmware to flash over the top of the Sky firmware that the router was programmed with already.

Before I go any further in explaining how I flashed my Netgear DG834GT, with Netgear’s own standard firmware, you should take note that the following procedure may ‘brick’ or render your router useless (as happened to a friend of mine!). You flash it at your own risk!

Firstly disable any firewall software you may have installed on the computer you are using such as ZoneAlarm or Norton Personal Firewall.

Grab the following files from here:

Firmware version 1.02.13 (latest version at time of writing)
Firmware version 1.02.04
Recovery Utility

Now copy all 3 files onto a Windows XP computer, this is very important because the Netgear recovery utility does not work properly in Windows Vista. It results in a bluescreen when you try to flash the firmware and renders the router useless. If you are using Vista do not try to flash it.

Unzip the recovery utility to a new folder and copy the firmware file that you downloaded for version 1.02.04 (filename dg834gt_1_02_04.img) into the same folder as the files for the recovery utility. (The recovery utility automatically detects the firmware in the same location as the utility and uses this for the flash). So basically we are going to flash the router with version 1.02.04 of the firmware first. I have not tried flashing it with the newer firmware at this stage, all documentation I have read on flashing the router at this point uses version 1.02.04 to flash the device. (I will explain how to upgrade to the latest firmware later on). So you should now have a folder layout like this:

Plug the Ethernet cable from your Windows XP computer into one of the LAN ports on the router. Now plug the transformer for the Netgear router into the wall and turn it on, do not plug the power into your router at this stage. Now grab a pen or paperclip, hold your router with one hand and use the pen or paperclip to hold the reset button in on the back of the router and at the same time plug the power cord into the back of the device. Continue holding the reset button down for 3-4 seconds and then remove the pen or paperclip. Now look at the front of your router, you should see the two lights (the power and the test light) on the left hand side of the router flashing alternately. If they are not flashing alternately repeat the procedure until they are.

Now that the lights are flashing alternately on the front of the router, run the file RmDrv.exe in the Netgear recovery utility folder. Once you have run this utility run UpgradeWizard.exe to start the flashing process. Firstly click next to confirm you wish to upgrade the firmware for your router:

Secondly select the network card that you have in your Windows XP computer that has the Ethernet cable plugged into it. You may see more than one device here including wireless network cards and firewire cards. Click next when you have chosen the correct network card:

Now you will see a list of devices connected to the Windows XP computer through the network card that you chose on the previous screen. Since the router has not fully initialised (because the reset button was held in when the router was turned on) it will not have given your network card an IP address. So in this list you should see only a single MAC address of the Netgear router we want to flash. Click next to continue:

Now you are prompted to upgrade the firmware on the router. You will see a progress bar on the bottom of the screen, when it reaches 100% you know the flash has completed. Upgrade the firmware as advised. When I flashed my router it took about 5 minutes to complete the flashing process. When it was complete I turned the power to my router off, waited 10 seconds and turned it back on again.

When you turn the router back on access the admin web interface by typing the following URL into the browser of your Windows XP computer:

http://192.168.0.1

You will be prompted for a username and password. Sky’s default settings are as follows:

Username: admin
Password: sky

Try these to log into the router, if successful you will be presented with the Netgear admin web interface. If the above username and password do not work, turn the router over, and whilst it is still powered on, use the pen or paperclip to push and hold the reset button on the back of the router for 10 seconds. Now wait for the router to initialise (the lights on the front of the router will settle) and try login to the router using the same URL above and the default Netgear username and password:

Username: admin
Password: password

Now that you are logged into the router upgrade the firmware to the latest version (filename dg834gt_1_02_13.img) by browsing through the menu:

Maintenance -> Router Upgrade

Click the browse button within the admin web interface and find the latest firmware - dg834gt_1_02_13.img. Now click upload to upload the newest firmware on your Netgear DG834GT router. Once this completes you may have to log into the router again using the same username and password as you did previously. Check that your router is running the latest firmware by browsing through the menu:

Maintenance -> Router Status

The firmware version should be the same as the version you just uploaded to the device. Your Netgear DG834GT is now running the latest version of Netgear’s own firmware and the device will work with any ISP, including Sky.

One last note, If you had to login to the router using:

Username: admin
Password: sky

You will probably want to reset your router back to its factory default settings by using a pen or paperclip to push and hold the reset button on the back of the router for about 10 seconds whilst the device is powered on.