If you align your virtual disks the performance of your VM:s increases. The only problem is when you have a n already installed VM that doesn’t have aligned disks.
Do you really want to create a new VM with aligned disks and then install the OS, VMware tools, applications etc?
I found a great guide on how to align partitions without losing data on tuxyturvy.com.
It basically boils down to the following:
1. Make sure the disk is defragmented
2. Boot the system with the Gparted live CD.
3. Select the parition you are wanting to resize and choose (Move/Resize)
4. Shrink the volume by some amount, the smaller you shrink it the faster it will copy during the move step. I usually shrink it a GB or so larger than the amount of data on the drive.
5. Move the partition to right by a few MB’s to free up space at the start of the disk.
6. Once the move completes, exit Gparted, not the entire live CD, just the Gparted application
7. Start the terminal window on the live CD
8. In the command window type ‘parted /dev/sda’ (substitute your actual device here) to start the command line parted editor
9. Create a new partition at the start of the disk to fill in the space up to the section where you want to align your parition. For example, if you want your system partition to start at sector 128, create a very small partition that takes up space from sectors 63-127. The command would be something like this:
mkpart primary 63s 127s
This tells parted to create a new primary partition from sector 63 to sector 127. That means the very next sector available is 128, a stripe aligned partition. You may want a different start sector based on your array (some use 64K, some 128K, some bigger) but I’ve found the 128K alignment to work well with both 64K (Equallogic) and 128K (EMC Clariiion) stripe sizes.
10. Exit parted and restart the Gparted GUI by clicking the Gparted icon.
11. Use the Move/Resize option to resize the NTFS partition to fill the entire remaining space. As pointed out by several users, you MUST uncheck the “Round to Cylinders” option prior to this. I guess I thought this was obvious since we’re trying to align to a specific sector but that’s why I’m not a documentation writer.
12. Exit gparted, run parted again, remove the small partition you created earlier and reboot.