Avago Technologies Syncro CS 9286-8e - Manual (Page 8)

Avago Technologies
- 8 -
Syncro CS 9286-8e Solution User Guide
November 2014 Chapter 1: Introduction
Performance Considerations
In a configuration with multiple VDs, the workload is typically balanced across controllers to provide a higher degree
of efficiency.
When a controller requires access to a remote VD, the I/Os are shipped to the remote controller, which processes the
I/O locally. I/O requests that are handled by local VDs are much faster than those handled by remote VDs.
The preferred configuration is for the controller to own the VD that hosts the clustered resource (the MegaRAID
Storage Manager utility shows which controller owns this VD). If the controller does not own this VD, it must issue a
request to the peer controller to ship the data to it, which affects performance. This situation can occur if the
configuration has been configured incorrectly or if the system is in a failover situation.
NOTE Performance tip: You can reduce the impact of I/O shipping by
locating the VD or drive groups with the server node that is primarily
driving the I/O load. Avoid drive group configurations with multiple
VDs whose I/O load is split between the server nodes.
MegaRAID Storage Manager has no visibility to remote VDs, so all VD management operations must be performed
locally. A controller that has no direct access to a VD must use I/O shipping to access the data if it receives a client data
request. Accessing the remote VD affects performance because of the I/O shipping overhead.
NOTE Performance tip: Use the MegaRAID Storage Manager utility to verify
the correct resource ownership and load balancing. Load balancing is
a method of spreading work between two or more computers,
network links, CPUs, drives, or other resources. Load balancing is used
to maximize resource use, throughput, or response time. Load
balancing is the key to ensuring that client requests are handled in a
timely, efficient manner.