topic RAW Disk space setup in Operating System - Linux

RAW Disk space setup

MikeL_4 — Thu, 07 May 2009 12:29:05 GMT

I have a new server that has 3 LUN's attached on SAN device that I have multipathed: /dev/mapper/mpath1, mpath2, and mpath3

The DBA's want 80Gb on each LUN setup as RAW space for the database and the rest as LVM space...

Not sure how to set this up with the RAW space and rest to LVM???

Re: RAW Disk space setup

avizen9 — Thu, 07 May 2009 12:46:35 GMT

HI MikeL

first you need to create PV,VG and then you can create LVM

For RAW space follow as below.
lvcreate -l LExx -n lvoln -r N /dev/vgNUM

chown informix:informix /dev/vgNUM/rlvolxx
chmod 666 /dev/vgNUM/rlvolxx

you need to ask your DBA they want to use these raw space for which user and group, in above example its for informix user and informix group.

let me know how it goes, thanks,

Re: RAW Disk space setup

Ivan Ferreira — Thu, 07 May 2009 12:46:39 GMT

The way RAW devices are used vary depending of the Linux distro and version. What is your Linux version?

Probably you can partition a disk and use one partition as raw device and another as physical volume. I'm not sure about the performance impact of this configuration.

Re: RAW Disk space setup

MikeL_4 — Thu, 07 May 2009 12:58:07 GMT

This is on a Red Hat Version 5.3 server...

and for Oracle database....

Re: RAW Disk space setup

Ivan Ferreira — Thu, 07 May 2009 13:06:59 GMT

Please see:

http://www.held.org.il/blog/?p=32
http://run.tournament.org.il/raw-devices-for-oracle-on-redhat-rhel-5/comment-page-1/

Re: RAW Disk space setup

MikeL_4 — Fri, 08 May 2009 17:24:24 GMT

unfortunately DBA's want the space to be true RAW and not RAW under LVM....