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Home -> Community -> Usenet -> c.d.o.server -> Re: Async I/O
Hans-Peter Sloot wrote:
>
> Hello Stephane,
>
> I don't think that your statement is true.
> Oracle will be clever enough to open the redo log files
> with the O_SYNC flag.
I would say it depends on operating systems. I distinctly remember (well, a long time ago : t'was v5 then) that on some ports the documentation was explicitly stating that the only way to guarantee integrity was to use raw devices. I have not studied it in detail, but I am ready to bet that it is a similar reason why raw devices are required on DEC/Unix for intance with the Parallel Server Option. And even if redo log files are synchronously written (right, the example was perhaps not the most appropriate), and control files too, there is some need of synchronization between data, redo and data files, since the data file header contains the system commit number which enables Oracle to require a recovery if needed on startup. Be certain that if the Oracle support discourages something, it means there is a potential risk, however small and unlikely.
--
Regards,
Stéphane Faroult
Oriole Corporation
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