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Enterprise Storage Server (ESS)
ESS provides integrated caching and RAID support for the attached disk devices.
ESS can be configured in a variety of ways to provide scalability in capacity and
performance. One ESS can support in excess of 28 TB and can utilize 2 Gbps
Fibre Channel connectivity.
Redundancy within ESS provides continuous availability. It is packaged in one or
more enclosures, each with dual line cords and redundant power. The redundant
power system allows ESS to continue normal operation when one of the line
cords is deactivated.
ESS provides an image of a set of logical disk devices to attached servers. The
logical devices are configured to emulate disk device types that are compatible
with the attached servers. The logical devices access a logical volume that is
implemented using multiple disk drives. This allows ESS to connect to all IBM
servers, from zSeries to iSeries, pSeries and xSeries, directly or thorough a
SAN, thus helping the x440 fit into a heterogeneous environment containing a
variety of server architectures. ESS offers several choices of host I/O interface
attachment methods, including SCSI and Fibre Channel for xSeries.
For more information on the ESS go to:
3.3.2 Disk subsystem performance
Because of the processing capacity of the x440, a poorly designed storage
subsystem could become a bottleneck, seriously impacting overall system
performance. You should implement a disk subsystem that is able to efficiently
process the potentially massive number of disk I/O requests generated by the
processor subsystem.
Assuming that you will be implementing a RAID storage configuration, the rule of
thumb is that more physical disks will improve the throughput of your disk
subsystem and consequently overall system performance. In almost all
applications, adding disks to your RAID configuration will continue to improve
performance until another system component becomes a bottleneck. A storage
solution with too few physical disks will become a bottleneck for the entire
system.
You will need to carefully analyze your storage capacity requirements, your
application requirements, and your host requirements before you finalize your
storage solution.
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IBM ^ xSeries 440 Planning and Installation Guide
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