RE: Bigfile tablespaces on OS filesystems?
- From: "Allen, Brandon" <Brandon.Allen@xxxxxxxxxxx>
- To: "avramil@xxxxxxxxxxxxxx" <avramil@xxxxxxxxxxxxxx>, "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>
- Date: Mon, 21 Sep 2009 11:12:08 -0700
No, the entire 500GB won't have to be read every time the file is accessed -
the OS will do block-level IO just like ASM. The main difference is just that
the I/O will be buffered by the OS (unless you have filesystem with an option
for direct IO) so it might add a few microseconds to every I/O for the extra
memory-to-memory copy, and will waste some of your RAM for holding this extra
copy in the OS buffer in addition to Oracle's buffer. The file size doesn't
affect r/w performance - the number of disks, speed of disks, SAN cache, fibre
channels, etc. are what will affect the performance. I believe asynch IO on
HPUX is simulated with multiple Oracle DB writers so you might want to look
into that.
Regards,
Brandon
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