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I don't have a lot of knowledge on Linux so pleas forgive me if this is a simple question.

I manage a server with Oracle RAC 11g running on Redhat 5.2. There are a number of raw drives on the server but I cannot see how they are being mapped.

I have had a look at the fstab and even the udev (raw rules configuration, even thought its depreciated). But I cannot see where the various mappings from the partitions presented /dev/sd[xy][123] would map to the various /dev/raw/raw[12345] etc.

So is there any way I can work out which partitions are assigned to the mappings and the size of the partitions?

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You should be able to use:

# raw -qa
# # or
# raw -q /dev/raw/thedeviceyouwant

to list the mappings for existing raw devices. This will give you the mapped major/minor number for the mapped devices. ls -l /dev/sd* shows the major/minor number for the listed partitions/drives, so you can do the correspondence with that.

As for the size of the partitions (once you've found them), use fdisk (or cfdisk if you have that, or your favorite partition manager).

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/dev/raw is obsolete and should not be used any more. It also doesn't have anything to do with /etc/fstab, which specifies what partition should be mounted where in the filesystem.

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That doesn't answer the question, and doesn't help someone who has to manage servers with raw devices (which still happens today with large database installations whether it's "obsolete" or not). And what does that fstab remark have to do with the question? – Mat Jan 4 '12 at 21:14
@Mat, the question mentioned checking fstab. If you do have raw devices, fstab has nothing to do with them. If your db id still using raw devices, you should get it updated. raw was superseded by O_DIRECT like 7 years ago. – psusi Jan 4 '12 at 23:08

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