HP VMA Series, Инструкция по установке и обслуживанию

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Chapter 10 - Performance Tuning and Troubleshooting
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VMA-series Memory Array Installation and Service Guide HP-AM456-9002A Rev 01
Performance Tuning and Testing Overview
One of the primary reasons for choosing a Memory Array for block storage is
that a flash-based memory array enables you to extract maximum performance
from your applications.
But optimal performance is achievable only if the entire Memory Array system is
properly tuned. In many cases, the default settings provide for significant
application acceleration. Where this is not the case, a careful review of the
system defaults at each layer is recommended.
If any one layer is incorrectly sized or configured, the performance of the entire
application will be limited by this bottleneck. In an HDD-based system, the
physical disks are often an obvious performance bottleneck. In a flash-based
memory array, application performance bottlenecks may occur at any one of six
system layers;
• Flash-layer: The flash-based memory array configuration and attributes
• Network-layer: The PCIe cables, cards, and slots
• Host-layer: The processors, RAM, interconnects, and PCIe hubs
• Operating System-layer: The Linux or Windows operating system and its
buffer and I/O settings
• File System-layer: The file system and its settings such as block size,
snapshots, and logging
• Database-layer: The database (if used) and its configuration and
optimizations
In general, performance tuning and testing is a six-step process by which each
layer of the Memory Array system is tuned before moving on to the next layer in
the system.
Performance tuning and testing techniques for the higher system levels are
beyond the scope of this book. This chapter describes techniques for tuning and
testing the first two layers in the Memory Array system: the flash layer and the
network layer.
• Step 1: Flash-layer performance tuning : Ensure that the file system and
operating system are 4kB aligned. The
vpartial
and
vring
Utilities
enable you to identify 4kB alignment issues.
• Step 2: Network-layer performance tuning and testing : Network-layer
performance testing may be done in two phases. First, ensure that all of the
PCIe connections are high-bandwidth. Next, use the
perf_test
utility to
establish performance baselines for reads, writes, and mixed reads and
writes.
After the flash and network layers have been configured and tested, you may test
the performance of the higher system layers.