[linux-lvm] Using Oracle with lvm AND rawio: read(512) from

Michael Tokarev mjt at tls.msk.ru
Mon Dec 4 14:42:14 UTC 2000

Jorg de Jong wrote:
> Hi Michael,
> I had a look at you original message and I found two things;
> - the man page of raw says that you can not use dd on a raw device !?!

This is because of (possible) alignment problems.  Dd command that I use aligns
data accordingly, it seemed to be.  At least I didn't noticied any problems
using it with plain "rawed" partitions, as shown by my examples, and it
works well with raw device on top of lvm volume, as long as I specify
block size 1024, 2048 etc, but NOT with 512 (default) blocksize.

> - further more I suspect that it might be the case that our logical volume is
> to small to create the requested table on.

I'd think that 128Mb volume is sufficient for 10Mb tablespace... ;)

> The oracle documentation says on the subject :
> >Raw Device Setup
> >
> >Keep in mind the following items when creating raw devices:
> >
> >    When creating the volumes, ensure that the owner and group are oracle and oinstall, respectively.

If oinstall group used at all.  That devices simple should be read/writable by
oracle process owner, that's ok in my case:
  # ls -l /dev/raw/raw100
  crw-rw----    1 oracle   disk     162, 100 Aug 14 19:26 /dev/raw/raw100
  # _
If it where due to permissions problems, then plain partitions also
should not work (them works well), and oracle should return "permission
denied" error (that it does if I change permissions).


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