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

Andreas Dilger adilger at turbolinux.com
Fri Dec 1 23:22:20 UTC 2000

Michael Tokarev writes:
> The bad thing is that Oracle tries to write 512 bytes
> _when creating tablespace_ (I've set up it to use 4k
> blocks, so it will read/write 4096*n blocks after ts
> creation).  I attached some strace output from oracle
> process when creating tablespace, below.

One "hack" you could try when creating the tablespaces initially is
to symlink /dev/raw/raw100 to the block device you are using
(in this case /dev/vg0/ora0), and then when you are done with
the tabelspace creation remove the symlink and set up the raw
device as before.

I'm not 100% sure this will work, however.  Is the /dev/raw directory
a "virtual filesystem" like proc or /dev/shm?  The other possibility
is that Oracle will treat it differently because it is a block device
and not a character device, but I'm not sure of that either.

As to the real problem, I have no idea.  There were a couple of changes
that Heinz made to LVM w.r.t. block sizes, but I think that was limited
to removing constants, and not changing the actual block handling.

Cheers, Andreas
Andreas Dilger  \ "If a man ate a pound of pasta and a pound of antipasto,
                 \  would they cancel out, leaving him still hungry?"
http://www-mddsp.enel.ucalgary.ca/People/adilger/               -- Dogbert

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