Database Reference
In-Depth Information
system partition and the VMware vSphere VMFS partition are misaligned. In this case,
for every three backend IOs, you get one productive IO. This could have the effect of
causing each IO operation 3X latency, which is like getting 30% performance from your
100% storage investment. Fortunately, with Windows 2008 and above and with VMFS
volumes that are created through VMware vCenter, this problem is much less likely.
Figure 6.8
File system and storage that is not correctly aligned.
Starting with Windows 2008, all partitions are aligned to the 1MB boundary. This
means in almost all cases, they will be aligned correctly. The same is true with VMFS5
partitions created through VMware vCenter. They will align to the 1MB boundary.
However, if you have an environment that has been upgraded over time, you may still
have volumes that are not correctly aligned. The easiest way to check is to monitor for
Split IOs in both ESXTOP or in Windows Performance Monitor.
Figure 6.9
shows reading of one frontend block will require only one backend IO
operation, thus providing lower latency and higher IO performance.
