HP HP-UX11i: asynchronous I/O

About this task

Asynchronous I/O is very important to performance especially on high transaction volume processing environments. In summary, processes that issue synchronous read() or write() I/O calls must wait for the I/O to complete before it can continue. In contrast, processes can issue multiple asynchronous (non-blocking) aio_read() or aio_write() I/O calls in parallel without waiting.

HP-UX does not enable asynchronous I/O by default. HP-UX also only supports asynchronous I/O on files that reside on raw devices and not on filesystems. If you don't enable asynchronous I/O, workloads such as Oracle will try to run multiple DBWRs processes to get a limited amount of I/O parallelism.

To enable asynchronous I/O on HP-UX, you have to: