In order to know if your OS has async io enabled do a
bash-2.05# modinfo | grep -i aio
141 7828e000 4916 178 1 kaio (kernel Async I/O)
141 7828e000 4916 178 1 kaio (kernel Async I/O for 32 bit com)
if the kaio modules are loaded, you have async io enabled
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