Setting a raw device in RedHat/CentOS 5 for Oracle RAC

Apparently the issue got changed since RedHat 4, which had /etc/sysconfig/rawdevices, /etc/init.d/raw & /usr/bin/raw.

This version introduces /etc/udev/rules.d/60-raw.rules & /bin/raw.

A. Doing it manually (example):

/bin/raw /dev/raw/raw1 /dev/sdb1

of course, it’ll be forgotten after reboot. so:

B. Doing it the right way – udev (example):

  1. Add to /etc/udev/rules.d/60-raw.rules:
  2. ACTION==”add”, KERNEL==”sdb1″, RUN+=”/bin/raw /dev/raw/raw1 %N”

  3. [Optional] to set permissions, create a new /etc/udev/rules.d/99-raw-perms.rules containing lines such as:
  4. KERNEL==”raw[1-2]“, MODE=”0640″, GROUP=”oinstall”, OWNER=”oracle”

The header of rules.d/60-raw.rules file mentions that this method of using raw devices is deprecated. But still, I think that’s the only available way if one wants to use raw devices with Oracle RAC, Either for cluster issues (Voting+OCR) or simple Oracle data files.

C. Oracle RAC raw device permissions

You might ask: what permissions should I give the Oracle RAC disks? This is what I’ve found out with Roman, a DBA expert who came to help:

  • OCR Device(s): root:oinstall , mode 0640
  • Voting device(s): oracle:oinstall, mode 0660
    • CRS cannot run if user oracle can’t access the device!
  • Other devices (i.e. data): I guess also oracle:oinstall mode 0660, because oracle user might need to access them.

Disclaimer: I’m not a DBA expert; I hope this helps. Don’t blame me if it ruins important data; send comments if you think I’m wrong/right.

No Responses to “Setting a raw device in RedHat/CentOS 5 for Oracle RAC”

  1. [...] out the source of this information, at this entry about raw devices. I will add it here, anyhow, with a slight [...]

  2. Ralph G. says:

    TO All READERS: Do not follow this GUIDE! Its outdated!
    USE THIS:
    http://www.ardentperf.com/2008/02/13/oracle-clusterware-on-rhel5oel5-with-udev-and-multipath/

    RAW is not supported anymore!!

  3. Panco says:

    RAW device still support. OCFS is not stable in some case and ASM can’t support OCR and Voting, hence RAW is still the best option for OCR and Voting.

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