LAN adapters and fast disk subsystems. In contrast, database servers typically need fast processors (or multiple processors) and fast disk subsystems. Both file and database servers require large amounts of memory for operating system caching.
Tuning system performance involves determining where the current bottleneck is and then alleviating this bottleneck. For example, if the bottleneck is the processor, then a faster processor can be installed or alternatively, the CPU load can be reduced by using bus master LAN and disk adapters.
If the bottleneck is memory, then additional memory can be installed.
If the bottleneck is the disk subsystem, then either additional disks or disk adapters can be installed, or a specialized high performance disk subsystem such as an IBM Array Controller with IBM Fast
If the bottleneck is the LAN adapter, then a faster LAN interface such as the IBM LANStreamer MC 32 adapter with 40 MBps data streaming support can be installed. Another optimization technique that can be employed is to utilize multiple LAN adapters in the server increasing throughput onto one or multiple segments.
The network operating system can create bottlenecks in its use of system resources. For example, inefficient use of buffers will waste the memory resources and can cause a memory bottleneck.
The performance of a subsystem is often
5.1.1 General Performance Characteristics
The disk subsystem is a major component of server performance and is frequently the location of the server bottleneck. Performance efficiency of this subsystem depends on whether the disk cache is sufficiently large and intelligent enough to contain the correct data required to satisfy most network requests from cache. In addition, the hard disks themselves must be fast enough to provide read data for the cache and empty the cache quickly when data must be written to disk. Thus, the disk subsystem must offer performance that can keep the cache filled with useful data. Failure to do so results in a lower disk cache hit rate, slower user access times and decreased performance.
The LAN adapter must move data between the network and system memory as fast as possible. For applications that issue large read and write requests, the width of the adapter data bus is an important factor. For example, applications such as multimedia, which require high bandwidth data can benefit greatly by using
On the other hand, when an application transfers small data frames, latency or the time it takes to move a frame through the LAN adapter becomes a critical factor. The IBM LANStreamer technology can be of great benefit in these applications due to its low latency design.
