deactivate the cache for ext3

[Tonatiuh]

Red Hat Enterprise Linux 4.0

Ext3 filesystems have a proper cache that acts at operation system level. This is bad when using Oracle on that filesystems.

How can I deactivate the cache of the operating system?

(example: In HP-UX is just a kernel parameter)

[Ivan Ferreira · Accepted solution]

I think that in Linux, there is no parameter at kernel or mount level to disable de cache of the filesystem.

You can use raw devices, or at least, disable the "access time" timestamp update (noatime).

[Vitaly Karasik_1]

There are several relevant articles :

http://www.linuxjournal.com/article/8539 - Optimizing Oracle 10g on Linux: Non-RAC ASM vs. LVM

-http://www.oracle.com/technology/tech/linux/pdf/Linux-FS-Performance-Comparison.pdf
Linux FS performance comparison

[Gopi Sekar]

I am not sure whether you are talking about journaling option parameters. If you want to optimize on journal parameters then take a look at 'tune2fs' command.

Regards,
Gopi

[dirk dierickx]

there is no such thing in linux, you should not want to run a filesystem without cache to begin with.
access to devices without caching is provided through raw devices, as long as the program knows how to use them.

[Erez Kirson]

hey,

maybe you ment "noreservation"
try mounting your DB with this option
mount -o noreservation /mount

This is new with RHEL4 and 2.6 kernel.

it intends to improve file system layout,
not always good with DB.

hope it helps

E