Avago Technologies Syncro 9361-8i - Manual (Page 7)

Avago Technologies
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Syncro CS 9361-8i and Syncro CS 9380-8e Controllers User Guide
November 2014 Chapter 1: Introduction
Overview of the Hardware Installation, Cluster Setup, and Configuration
1.5 Overview of the Hardware Installation, Cluster Setup, and Configuration
Chapters 2 describes how to install the hardware and software so that you can use the fault tolerance capabilities of
HA-DAS to provide continuous service in event of drive failure or server failure and expand the system storage
Chapter 2 documents how to connect the CacheVault modules, and then install the Syncro CS controllers and the
remote mount boards in the CiB enclosure. In addition, it lists the steps required after controller installation and cable
connection, which include the following:
 Configure the drive groups and the virtual drives on the two controllers
 Install the operating system driver on both server nodes
 Install the operating system on both server nodes, following the instructions from the manufacturer
 Install StorCLI and MegaRAID Storage Manager™ utilities
Refer to the 12Gb/s MegaRAID SAS Software User Guide at http://www.lsi.com/downloads/ for information about
running the configuration utilities.
Refer to the Syncro CS 9361-8i and Syncro CS 9380-8e Solution User Guide at http://www.lsi.com/downloads/ for the
procedures used to perform the following actions after the hardware is fully configured and the operating system is
installed:
 Install and enable the Cluster feature on both servers.
 Set up a cluster under the supported operating systems
 Configure drive groups and virtual drives
1.6 Performance Considerations
SAS technology offers throughput-intensive data transfers and low latency times. Throughput is crucial during
failover periods where the system needs to process reconfiguration activity in a fast, efficient manner. SAS offers a
throughput rate of 12 Gb/s over a single lane. SAS controllers and enclosures typically aggregate 4 lanes into an x4
wide link, giving an available bandwidth of 48 Gb/s across a single connector, which makes SAS ideal for HA
environments.
Syncro CS controllers work together across a shared SAS link to achieve sharing, cache coherency, heartbeat
monitoring and redundancy by using a set of protocols to carry out these functions. At any point in time, a particular
VD is accessed or owned by a single controller. This owned VD is a termed a local VD. The second controller is aware of
the VD on the first controller, but it has only indirect access to the VD. The VD is a remote VD for the second controller.
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.