Re: raw partions vs file systems

Mick McRae wrote in message <3609F04E.3C256E3F_at_its.csiro.au>...
>Hi,
>
>I've only ever configured Oracle databases using Unix file systems. A
>site
>I'm starting with uses raw partitions. Do raw partitions provide
>significant performance increases?

Depends on many, many factors. In general, an I/O intensive database with multiple concurrent transactions will see more consistent, and better, performance with raw devices. This is why Oracle (Sybase, EMC, IBM, etc.) recommend them in such situations. The only way to really know is to *test* - you don't seem to have that choice in this case.

>I suppose the performance gain would
>want to be
>at least 10% for the additional overhead and limited flexibility of
>using raw partions.

You have no idea of the improvement without testing. Guessing is meaningless. The performance might even be worse.

As regards the 'additional overhead and limited flexibility of using raw partions', I don't understand what you mean? Get an OS with a decent LVM, and then raw partitions are more flexible and a lot less hassle than file systems (for which you have to mess about with raw partitions anyway). Only 'hassle' is backup. Learn 'dd' (on UNIX) or (recommended) get a backup product that supports raw (and preferably Oracle EBU or RMAN with raw devices) directly.

>
>We run Oracle7/Oracle8 on Solaris 2.5.1/2.6. As a scenario, assume a
>5GB
>and 10GB database. Also, what are the differences if the database is
>predominantly read-only as opposed to write intensive. The
>filesystems/rawpartions are striped and mirrored, although this does not
>
>necessarily have to be the case.
>
>Any input appreciated

Again, any reply is guesswork and utterly meaningless. Do some testing - it's fun! :-)

Regards,

MotoX.

>
>Regards,
>Mick
>
Received on Mon Sep 28 1998 - 04:28:21 CDT