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 1 illustrates the logical device file name of the device that the application uses, for before and after HDLM installation.
|
Host status |
Device file name that the application uses |
|---|---|
|
Before installing HDLM |
The application uses the logical device file name for the SCSI device. |
|
After installing HDLM |
The application uses the logical device file name for the HDLM device. |
The logical device file name of an HDLM device has the following format:
/dev/sddlm[aa-pop][1-15]- About alphabetic letters used in the logical device file name:
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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.
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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 specifiable range of values for the second character is from a to o.
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A major number is required for each of the first characters.
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The following figure shows information about alphabetic letters used in the logical device file name.
- About numeric values used in a logical device file name:
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[1-15] indicates a partition number in the applicable LU. When the HDLM configuration definition utility (dlmcfgmgr) is executed, all logical device files for partitions 1 to 15 are created.
For example, if the logical device file name of an HDLM device is sddlmaa1, it indicates partition 1 on sddlmaa. To specify the entire LU, simply use sddlmaa. Note that HDLM creates block device files. The system dynamically selects the major number of the block device that this file uses.