Re: Raw Disk Partition vs. Unix File System (Oracle 6)

In article <CBuyrL.DLo_at_cbnewse.cb.att.com>, richard.dib <cafe_at_cbnewse.cb.att.com> wrote:
>
>Here are my questions:
>
>- Does anybody have any experience with Oracle using a raw disk partitition
> instead of the Unix file system? Could you share your experiences?

I've used raw devices with Oracle 6 for several years, and only had one bad experience (when a system admin put swap space on top of a data file). It is more difficult to administer in many environments, since it is hard to adjust disk layout on the fly (you typically have to reslice your disk). However, with planning I haven't found this to be that much of a problem.

>- What are the benefits? Is the improvement in performance worth the work?

Benefits are improved integrity (don't have to worry about whether UNIX buffers were flushed at the time of a crash), and performance improvements. I have never benchedmarked the difference in performance, but it makes sense to me to believe there is one.

>- How easy would it be to backup this database? We are currently using a shell
> script to do this.

You'll probably have to change it (although we wrote our backups to handle either UNIX file system files or raw devices). Since cpio/tar won't back up the contents of raw devices, you typically have to use "dd" (and some custom scheme to track the tape contents).

-Dave.

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