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 1 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 1 were measured by using LVM1 commands. LVM2 commands show little difference before and after HDLM installation.

# 1

CPU: Pentium III 1.4 GHz x 2

Memory: 1 GB

Connection between host and storage systems: 64 LU x 2 paths (total 128 paths)

# 2

CPU: Xeon 2.0GHz x 2

Memory: 2 GB

Connection between host and storage systems: 64 LU x 2 paths (total 128 paths)