Tuning I/O resources

Tuning disk I/O-bound systems

If the system is I/O bound because of disk activity, there are a number of things that can be done:

You may find that the performance of the system can be improved slightly by increasing the values of the BDFLUSHR and NAUTOUP kernel parameters. This will reduce the number of times the disk will be accessed because blocks can be updated more often in memory before they are written to the disk. The inherent risk is that more data will be lost if the system crashes because it will be longer since it was last written to the disk. It is considered good practice to protect mission-critical systems against power failure using a UPS or similar device.

Various disk organization strategies are discussed in ``Overcoming performance limitations of hard disks'' which includes suggestions for optimizing your current hardware configuration.

Disk manufacturers implement various hardware and firmware (software in the disk controller) strategies to improve disk performance. These include track caching and varying the number of disk blocks per track across the disk surface. Usually, you have no control over such features.

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SCO OpenServer Release 5.0.7 -- 11 February 2003