Naming Conventions

The naming of raw devices and controller varies by Linux distribution.

• On Red Hat, the device name is /dev/raw/raw<number> and the controller is /dev/rawctl

• On SuSE SLES 11 versions, the device name is /dev/raw/raw<number> and the controller is /dev/raw/rawctl

Raw I/O Setup Steps

1. Select a shared disk partition of appropriate size for the SAP DB device space.

2. Bind an unused raw device node to this partition. Since this needs to be done every time the machine is rebooted and requires root access, you may want to add the raw bindings to a system initialization file (i.e. rc.local or boot.local). These bindings must be removed from the file once the hierarchy is under SPS protection. SPS will re-establish the raw bindings for raw I/O devices that are under SPS protection. Use the command raw –qa to see which raw device nodes are already in use. For example:

# raw –qa

# raw /dev/raw/raw1 /dev/sda1

3. Set global read permissions on both the raw device controller (/dev/rawctl or /dev/raw) and the disk partition on all servers that will protect the database instance.

# chmod a+r /dev/rawctl (or chmod a+r /dev/raw )

4. Set group and user read/write permissions on the raw device on all servers that will protect the database instance.

# chmod 664 /dev/raw/raw1

5. Change the owner of the raw device to the SAP DB OS User for the given database instance on all servers that will protect the database instance.

# chown –R sapdb:sapdb /dev/raw/raw1

6. Add the device space to the database using param_adddevspace or db_adddevspace. Refer to the SAP DB User Manual and/or the Database Manager CLI Manual.