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Raw devices using Oracle8i

Andrew R.

Raw devices using Oracle8i

We are planning to host a new database oracle8i (with replicator) and implement MCSG. The DBA mentioned that he's planning to use raw devices, I've set-up lots of clusters before but I never use the raw devices. Does any one has any experience in this field, Is it a must or preferrable to use raw devices and how ?

Thanks for your help
Live for the infinity life
harry d brown jr
Honored Contributor

Re: Raw devices using Oracle8i


click on "search" to the left under IT Resource Center and enter this in the search string:

+oracle +cluster +raw +disk

Make sure to click on the "FORUMS" radio button.

live free or die
Live Free or Die
Graham Cameron_1
Honored Contributor

Re: Raw devices using Oracle8i

Your DBA is a masochist.
Searching the links as suggested by Harry will show that the disadvantages of raw disks far outweigh the benefits.
I know, I've been there.
Computers make it easier to do a lot of things, but most of the things they make it easier to do don't need to be done.
Respected Contributor

Re: Raw devices using Oracle8i


Your DBA will certainly say that raw devices run faster than filesystem.
That's right some times ago.

In an MCSG cluster, I prefer filesystem with "mincache=direct" option of mount.

This option disable LVM cache (this is what you do when you use raw device).

In order to use thgis option, you must have "online JFS", a product that you should purchase in a MCSG cluster.


Carlos Fernandez Riera
Honored Contributor

Re: Raw devices using Oracle8i

Not so dificult..., just a different way..
Ron Gordon

Re: Raw devices using Oracle8i

Using MCSG and oracle OPS you are required to use RAW devices. I am not sure about replicator. Once you use raw devices its easy. The hardest part is making sure the device partition size say 100M raw partition equals the tablespace size 100*1024*1000 - 2*db_block_size If you don't use this formula you will be wasting space in the 100M raw partition.
Frequent Advisor

Re: Raw devices using Oracle8i

Don't use raw devices. There is little or no advantage,only an administration nightmare.