Create symbolic links to raw devices (UNIX)

Use symbolic links to assign standard device names and to point to the device.

To create a link between the character-special device name and another file name, use the UNIX link command (usually ln). To verify that both the devices and the links exist, run the UNIX command ls -l (ls -lg on BSD) on your device directory. The following example shows links to raw devices. If your operating system does not support symbolic links, hard links also work.
ln -s /dev/rxy0h /dev/my_root # orig_device link to symbolic_name
ln -s /dev/rxy0a /dev/raw_dev2
ls -l
crw-rw---  /dev/rxy0h
crw-rw---  /dev/rxy0a
lrwxrwxrwx /dev/my_root@->/dev/rxy0h
lrwxrwxrwx /dev/raw_dev2@->/dev/rxy0a

Why use symbolic links? If you create chunks on a raw device and that device fails, you cannot restore from a backup until you replace the raw device and use the same path name. All chunks that were accessible at the time of the last backup must be accessible when you perform the restore.

Symbolic links simplify recovery from disk failure and enable you to replace quickly the disk where the chunk is located. You can replace a failed device with another device, link the new device path name to the same file name that you previously created for the failed device, and restore the data. You are not required to wait for the original device to be repaired.

Copyright© 2018 HCL Technologies Limited