HP Hitachi Dynamic Link Manager Software - Manual (Page 670)

Notes on the /proc/partitions File
The HDLM device and each partition of the HDLM device that is recognized by
Linux and can be used are recorded in the /proc/partitions file. The /
proc/partitions file records the I/O statistics per device; however, it does
not record the I/O statistics of the HDLM device. The I/O statistics are always
0.
If you are going to obtain statistics about an HDLM device, perform
calculations by using the value recorded for the SCSI device that corresponds
to the HDLM device. The following is an example of output statistics.
Figure A-1 Example of a Displayed /proc/partitions File
Notes on Linux Commands
When a host and storage system are connected by multiple paths, HDLM uses
all of these paths as HDLM devices. Consequently, with Open() and Close()
system calls to the HDLM device, open or close processing occurs on each of
the multiple paths. Linux commands that issue successive Open() or Close()
system calls to multiple HDLM devices, such as the lvmdiskscan or pvscan
commands, will take longer to execute after HDLM is installed.
Table A-1 Examples of Linux Command Execution Times on page A-3
describes examples of how long the execution of these Linux commands can
be expected to take before and after HDLM installation. The execution times
shown in Table A-1 Examples of Linux Command Execution Times on page
A-3 were measured by using LVM1 commands. LVM2 commands show little
difference before and after HDLM installation.
A-2
Notes on Linux Commands and Files
Hitachi Dynamic Link Manager User Guide for Linux ®