I found that the partition table for vSphere 4 is totally different as ESX 3.5 did. At 1st was confusing as I only have 1 logical drive with RAID 1 configuration on my vSphere 4 machine, but when I did the cat /proc/partitions, it showed as 2 physical devices as sda and sdb.

I tested to delete the partition table from the fdisk utility as I did on usual Linux, but is not success. The system will roll back to the existing partition table before I tried to make the changes automatically. You may see the IO error happen when you try to write the partition table. At the same time, I found that there is a vmdk with similar 8GB of flat file and vmdk was created on the existing datastore which reflect the local storage on the vSphere host. It is viewable through CLI and vCenter client both. After some research, looks like the virtual disk is referring to vSphere core module and important mount point such as / & /var/log. Whenever I tried to remove the virtual disk from the ESX host, I get denied with error message of the virtual disk in use.

This 2 screen shots had helped me to understand that the new system partition method in vSphere 4, which is totally different as it did in ESX 3.5. At the mean time, I also found that to format the rest of the unclaim partiton on the local HDD for VMFS 3 file system as Datastore is compulsory during the setup too. Therefore, sizing on the partitions require to be planned prior to final deployment.

Related posts:

1. Participate in new version of vSphere Beta?
2. Apply VMware vSphere 4 Update 1 Patches
3. NFS ISCSI and FC Storage on vSphere

Click here to enlarge the picture

Attach is the screen shot which is been captured during my test.  Our ESX server is connected with 2Gb fiber channel dual connection from the ESX host to the Fiber Switches in our environment. If we do a calculation, 190MB/s will be 1520 Mb/s which is 76 % of the 2Gbps FC connection utilization. In between, there will always be some latency lost from the host level to our FC storage. My SAN storage is currently 75% populated with disks in active, this performance is consider good enough for my personal point of view. Bear in mind, this is only utilize 1 physical FC connection from my ESX host. Another interesting we found, that my R900 with more than 35 VMs per host, in the peak hour, it will not go more than 50MB/s. In this case, it seems that our environment is still under utilize from the I/O perspectives. Now it came to the point that, we had invested so much money on the fiber switches but we did not fully utilize the resources we have. Imagine that each ESX server will consume 2 HBA connection, and we only utilize less than 50% of the available bandwidth. The next move, I will definitely looking for something to reduce the FC ports utilization on our VM farm and data center as well. I know Xsigo and Cisco both have their idea to do this. You may need to have a look on VP780 from Xsigo or Cisco Nexus 5000 or 7000 for the next generation data center switches.

Related posts:

1. FCoE in the Data Center
2. Server Virtualization & Cloud Computing Model