Raw devices using Oracle8i

[Andrew R.]

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

[harry d brown jr]

Andrew,

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
harry

[Graham Cameron_1]

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.

[MARTINACHE]

Hi,

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.

Regards,

Patrice

[Carlos Fernandez Riera]

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

[Ron Gordon]

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.

[UNIXTEK]

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