HP StorageWorks HSG80 ACS Solution Software V8.8 for Sun Solaris Installation and Configuration Guide (AA-RV1RA-TE, March 2005)

FC Configuration Procedures
158 HSG80 ACS Solution Software V8.8 for Sun Solaris Installation and Configuration Guide
Servers
Servers are the computing power and the communication access for the storage
that the computing applications require. Servers can connect to local storage or
RAID Arrays. Many have tried to characterize the loading of a server in relation
to a “number of” quantities involved in a server-storage relationship.
Commonly described in the loading relationships are considerable factors that
include the:
■ Number of adapters on a server, and
■ Number of RAID systems that may be connected to an adapter.
A server may have up to four adapters and may connect up to four RAID arrays.
These numbers represent a relatively safe area of loading and are acceptable for
most general usage server-storage situations. For some servers (for example, in
the 4m class), these values may be too high; and for other servers (for example, in
the 4u class of Enterprise servers), these numbers may be too low. The maximum
number of adapters is only limited by the number of available expansion slots. Up
to 24 adapters have been tested simultaneously in a mainframe-class machine
(E10000).
These numbers, however, do not stand alone when describing a load on a
server-storage system. The key values are the actual I/O loading from server to
storage. The major components of I/O values are:
■ Reading versus writing data
■ Size of the records being read/written, and
■ Frequency of data to/from a storage device.
The following set of major components also has a large impact on the viability of
a configuration from the RAID array point of view:
■ Nature of the controller (SCSI versus Fibre Channel)
■ Amount of cache on the controller, and
■ Configuration of the disks enclosed by the RAID Array.
A specific configuration may or may not replicate the tested laboratory
configurations. When treating a specific configuration, the best guideline is to
determine the viability of a configuration that is applicable to your environment.
Additionally, while a given configuration may support the desired I/O quantity, it
may not support a desired performance characteristic of the I/O. Thus, both
configuration and performance can be best described with some test trials of a
specific configuration.