Notes on installing HDLM in a boot disk environment

Note the following when using HDLM on a boot disk:

• The storage system for which the boot disk will be created must satisfy the following conditions:

  • The storage system supports the boot disk functionality even if HDLM is not used.

  • HBAs support startup from the storage system.

• When you install the OS, create the root directory (/) and the /boot directory in separate partitions.

• When you use HDLM as a boot disk, do not specify an HDLM device for the kernel parameters resume, journal, and dump.

• When Red Hat Enterprise Linux, or SUSE LINUX Enterprise Server is used, HDLM supports environments that use LVM2 as a boot disk.

• For SUSE LINUX Enterprise Server 15 SP5, the following RPM package must be applied:

  • systemd-249.17-150400.8.40.1.x86_64.rpm or later

• For SUSE LINUX Enterprise Server 15 SP5, if you use an environment where a logical volume (LVM2) on an HDLM device is used as a boot disk, the following RPM package must be applied:

  • lvm2-2.03.16-150500.7.3.1.x86_64.rpm or later

• If you changed the configuration during startup or if the /etc/fstab file settings are incorrect, the system might not start.

• If the root directory (/) has not been mounted at startup, you cannot collect a boot error log (/etc/opt/DynamicLinkManager/hdlmboot.log). In this case, if a problem occurs, use the log displayed on the console to analyze the problem.

• The dlmcfgmgr log created at startup is output to /etc/opt/DynamicLinkManager/hdlmboot.log.

• When you restart in an environment where HDLM is installed on the boot disk, the following message is output to syslog. It is not an issue, so you can ignore it.

  systemd[1]: /usr/lib/systemd/system/hdlm-initrd.service:5: Unit dependency type RequiresOverridable= is obsolete, replacing by Requires, please update your unit file

• In an environment where an HDLM device is to be used as the boot disk, make sure that y is specified for hdlm_dracut in the /etc/opt/DynamicLinkManager/hdlm.conf file. If you want to set hdlm_dracut=n, do so when you create an initial RAM disk image file for the SCSI device.

• Once you have built an environment for starting the OS from an HDLM device, you cannot change the boot disk.

• If you do not use the storage systems disk set for the boot disk, before you install HDLM, edit the /etc/fstab file in the following manner to disable the LABEL specification and enable the sd device specification.

  1. Check the installation directory of the OS specified in the LABEL setting.

     # cat /etc/fstab
     LABEL=/    /    ext3    defaults    1 1
     LABEL=/boot    /boot    ext3    defaults    1 2

     Confirm that LABEL indicates the root directory and the /boot directory.

  2. Check the correspondence between the LABEL setting and the sd device.

     # mount
     /dev/sda2 on / type ext3 (rw)
     none on /proc type proc (rw)
     none on /dev/pts type devpts (rw,gid=5,mode=620)
     usbdevfs on /proc/bus/usb type usbdevfs (rw)
     /dev/sda1 on /boot type ext3 (rw)
     none on /dev/shm type tmpfs (rw)

     Confirm that the root directory is /dev/sda2, and the /boot directory is /dev/sda1.

  3. Using an editor such as vi, change the LABEL specification to an sd device specification.

     (before)

     LABEL=/    /    ext3    defaults    1 1
     LABEL=/boot    /boot    ext3    defaults    1 2

     (after)

     /dev/sda2    /    ext3    defaults        1 1
     /dev/sda1    /boot    ext3    defaults        1 2

  4. Install HDLM.

  5. After configuring the HDLM device, execute the dlmcfgmgr -o command to exclude the HDLM device that corresponds to the boot disk as a management target.

• If the SCSI device name has been changed by using the udev function, see BOOT_SETTING_UP_XEN=GUID-07C2F5FE-7561-46DC-B423-A2C9B671F65B=5=EN=.html and BOOT_PERFORMING_A_RE-INSTALLATION_OF_HDLM=GUID-05AE3AE2-401F-4E18-A655-C9D5A0884CB8=4=EN=.html and perform operations while reading the SCSI device names in those subsections as the new SCSI device names (udev name) that were changed by using the udev function.

  In an environment where HDLM has been installed, you can use the dlmcfgmgr utility to check the correspondence between a SCSI device and a udev name.

  The following shows an example of executing the dlmcfgmgr utility with the -v and -udev parameters specified.

  Figure. Example of executing the dlmcfgmgr utility with the -v and -udev parameters specified

  The HDevName, Device, and Udev columns display HDLM devices, SCSI devices, and udev names, respectively.

• To update the kernel package, you need to perform either of the following depending on which OS you are using:

  • When using Red Hat Enterprise Linux 7, 8, or 9:

    Refer to the information about updating the kernel package in UPDATING_KERNEL_PACKAGES_AND_APPLYING_OS_UPDATE_PACKAGES=GUID-ECAA03CC-C993-4FDC-A30F-026220B5B5F5=5=EN=.html.

  • When using SUSE LINUX Enterprise Server:

    You must first remove HDLM before updating the kernel package, and then re-install it after the update. Note that removing and re-installing HDLM might change the correspondence between HDLM devices and SCSI devices.

• To update the kernel package in an environment that satisfies the following conditions, you need to change the Persistent Binding setting:

  • The host is in a Hitachi Compute Blade environment.

  • The boot disk is managed by HDLM.

  • The Persistent Binding functionality is enabled.

  For details about the Persistent Binding setting, see the manual Hitachi Gigabit Fibre Channel Board User's Guide.

• The created LVM configuration does not change even if you perform an upgrade installation of HDLM.

• If you execute the dracut command or vgscan command when using a logical volume (LVM2) on the HDLM device in a boot disk environment, a message such as the following might be output temporarily. This does not affect HDLM operation.

  WARNING: Device mismatch detected for VG-name which is accessing SCSI-device-name instead of HDLM-device-name.

  or

  WARNING: Device mismatch detected for VG-name which is accessing SCSI-device-name instead of (null).

• When the logical volume (LVM2) on the HDLM device is used as a boot disk, the message below might be output when the server is activated. This does not affect HDLM operation.

  MM DD hh:mm:ss host-name kernel: dracut: Found duplicate PV pvid: using SCSI-device-name not SCSI-device-name

• For Red Hat Enterprise Linux 7, 8, or 9, Oracle Linux 7, 8 or 9, SUSE Linux Enterprise Server 12 or 15, Oracle Unbreakable Enterprise Kernel 7, or 8, install the LVM2 package even if LVM2 is not used.