Hitachi Dynamic Link Manager, User Manual

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2. HDLM Functions
17
2.6 Logical Device Files for HDLM Devices
The logical device file name of an HDLM device is different from the logical device
file name of a SCSI device. When you configure the logical device file of an HDLM
device for applications such as volume management software, these applications can
access the LUs that HDLM manages.
The following shows an example of the logical device file name that the application
uses to access the LU (for accesses before and after HDLM installation).
Table 2-5: Example of Using the Logical Device File Name of the Device Used When
the Application Accesses the LU illustrates the logical device file name of the device
that the application uses, for before and after HDLM installation.
Table 2-5: Example of Using the Logical Device File Name of the Device Used
When the Application Accesses the LU
The logical device file name of an HDLM device has the following format:
/dev/sddlm[
aa-pap
][
1-15
]
About alphabetic letters used in the logical device file name:
•
For the first 256 LUs, two alphabetic letters are assigned. The specifiable
values for the first two characters are in the range from
a
to
p
.
• For the 257th and subsequent LUs, three alphabetic letters are assigned. The
specifiable values for the first and third characters are in the range from
a
to
p
. The value of the second character is always
a
.
• A major number is required for each of the first characters.
Figure 2-6: About Alphabetic Letters Used in the Logical Device File Name shows
information about alphabetic letters used in the logical device file name.
Host status Device file name that the application uses
Before installing HDLM The application uses the logical device file name for the SCSI device.
Example:
sda
sdb
After installing HDLM The application uses the logical device file name for the HDLM device.
Example:
sddlmaa