VM performance is ultimately determined by the underlying physical hardware that serves as the foundation for your virtual infrastructure. The construction of this foundation has become simpler over the years, but there are still several areas that should be fine-tuned in order to maximize the VM performance in your environment. While some of the content of this writing will be generic toward any hypervisor, this document focuses on VMware ESX(i) 4.1. This is an introduction to performance tuning and not intended to cover everything in detail. Most topics have links to sites that contains deep-dive information if you wish to learn more.
Thursday, December 2. 2010
vStorage API's for Array Integration (VAAI) product demo
The vStorage API for Array Integration (VAAI) is a new API for storage partners to leverage as a means to speed up certain functions that, when delegated to the storage array, can greatly enhance performance. This API is currently supported by several storage partners and requires these partners to release a special version of their firmware to work with this API. In the vSphere 4.1 release, this array offload capability supports three primitives:
- Full copy enables the storage arrays to make full copies of data within the array without having the ESX server read and write the data.
- Block zeroing enables storage arrays to zero out a large number of blocks to speed up provisioning of virtual machines.
- Hardware-assisted locking provides an alternative means to protect the metadata
http://www.vmware.com/files/pdf/techpaper/VMW-Whats-New-vSphere41-Storage.pdf
Storage I/O Control product demo
With the release of vSphere 4.1, storage IO Control allows cluster-wide storage IO prioritization. This allows better workload consolidation and helps reduce extra costs associated with over-provisioning. Storage IO Control extends the constructs of shares and limits to handle storage IO resources. The amount of storage IO that is allocated to virtual machines during periods of IO congestion can be controlled, which ensures that more important virtual machines get preference over less important virtual machines for IO resource allocation.
When Storage IO Control on a datastore is enabled, ESX/ESXi begins to monitor the device latency that hosts observe when communicating with that datastore. When device latency exceeds a threshold, the datastore is considered to be congested and each virtual machine that accesses that datastore is allocated IO resources in proportion to their shares and is set per virtual machine. The number can be adjusted for each based on need. Low priority VMs can limit IO bandwidth for high priority VMs and storage allocation should be in line with VM priorities.
This feature enables pre-datastore priorities/shares for VM to improve total throughput and has Cluster level enforcement for shares for all workload accessing a datastore. Configuring Storage I/O Control is a two-step process:
1. Enable Storage I/O Control for the datastore.
2. Set the number of storage I/O shares and upper limit of I/O operations per second (IOPS) allowed for each virtual machine. By default, all virtual machine shares are set to Normal (1000) with unlimited IOPS.
Duncan Epping : Storage IO Control, the movie
Scott Drummonds : Storage IO Control
VirtualMiscellaneous : Storage IO Control - SIOC