topic Re: raw devices & data corruption in Operating System - Linux

raw devices & data corruption

Jorge Cocomess — Wed, 02 Aug 2006 19:01:45 GMT

Hi,

Anyone here running raw devices and experienced data corruption within these raw devices?

I am currently running RHAS 3.0 i64, Oracle 10g -- I had an option to run either Linux FS or raw devices when setting up RAC. However, I heard ASM doesn't like Linux FS, but does compatible with raw devices. Therefore, I went with the raw methodology.

Can someone shine some lights on this subject?

Thank you and have a great day!
J

Re: raw devices & data corruption

Steven E. Protter — Thu, 03 Aug 2006 01:46:28 GMT

Shalom,

I've run oracle and Software AG databases on a number of platforms including linux raw devices.

I've never had a data corruption problem that was related to the raw device. I've seen a problem where two nodes of a cluster when active on a raw device and corrupted the data in the raw device.

Raw devices are something I avoid, because I like to see files that I can copy. In your case, I think raw devices are a better idea.

You have to use database utilities to see whats going on inside and thats annoying, but you will get used to it.

My boss does soft links to the raw devices on a filesystem to make peole aware that they are there and what they are for. That is kind of a neat trick you might want to try.

SEP

Re: raw devices & data corruption

Jorge Cocomess — Thu, 03 Aug 2006 10:22:27 GMT

Sep - You mentioned soft link to raw devices. How do you do that and where can I find some details for this method?

Many thanks!!
J

Re: raw devices & data corruption

TwoProc — Thu, 03 Aug 2006 12:21:20 GMT

Jorge,

I think what Steven is referring to would be something similar to:

If you've got a physical device at say,
/dev/sdd4 and that's file one for tablespace ERPDDATA, then just make a symbolic link for it.

cd /dev
ln -s sdd4 ERPDDATA01 -
so, you'd see
a listing for /dev/ERPDDATA01 in dev and an "ls -l" command would tell what you it's really pointing to.