Create and use raw devices in linux

Create and use raw devices in linux-Linux Enterprise Application-Linux server application information. For details, refer to the following section. Several rac Installation tests have been performed on the VM Based on redhat AS4 over the past few days. Each time raw device files are created, a summary is provided and the concept is analyzed. The creation process is as follows:

1. Use fdisk/dev/sdb to divide devices. For example, you can divide a real disk into several shards corresponding to available raw files.

Fdisk/dev/sdb
3/dev/sdb1, dev/sdb2,/dev/sdb3

2. Map the original device to the partition created in the previous step. Modify the following file so that raw must be bound to the partition.
Vi/etc/sysconfig/rawdevices

/Dev/raw/raw1/dev/sdb1
/Dev/raw/raw2/dev/sdb2
/Dev/raw/raw3/dev/sdb3

3. To make the ing take effect immediately, run the following command as the root user:
#/Sbin/service rawdevices restart
# Chown oracle: dba/dev/raw [1-3]
# Chmod 660/dev/raw [1-3]

4. raw devices will be remapped during boot. By default, the owner of the original device is changed to the root user during boot. If the owner is not an oracle user when it is used by an oracle user, you can run the/etc/udev/permissions command. d/50-udev.permissions add comments for the raw line "raw/*: root: disk: 0660,
# Raw/*: root: disk: 0660
Then add a new line "raw/*: oracle: dba: 0660 ".
Raw/*: oracle: dba: 0660 --- if used by other users, you can change the user name

Run #/sbin/service rawdevices restart to make it take effect.

5. raw-qa can view raw information

You can create a connection to point to a raw file when using oracle.
Ln-s/dev/raw/raw11 redo101.log
Ln-s/dev/raw/raw12 redo102.log
Ln-s/dev/raw/raw22 redo103.log