https://hwengineer.blogspot.com/2018/07/redhat-ppc64le-os-disk-mirroring-sw.html

For information on configuration and restore operations ppc64le (POWER8) based on the Ubuntu SW RAID, see http://hwengineer.blogspot.com/2017/03/ppc64le-power8-ubuntu-sw-raid.html

In Ubuntu ppc64le environment, you can configure OS mirroring for the mdadm device (SW RAID1) 2 through disk configuration. Unlike the x86 architecture, in ppc64le architecture, PReP partition has to be called to hold the boot loader. However, this is not a mirror to mdadm. However, if the boot loader is installed again because there happens to be added to the write, a source with the dd command in the target release only copy left no hindrance in using the OS mirror. Using a small trick during the OS installation, first create all partitions on both sides, including the PReP disk, mdadm device was to keep walking only remaining device ppyaen the PReP.

The AC922 server with POWER9 and V100 are mainly used in the Redhat. Until now, what is this possible in Redhat OS mirror? Unfortunately Redhat installer can not determine if you want to be different, giving different from Ubuntu installer, first created after the partition using either partition into what each of the disk during the OS installation, first specify the partition applications are generated automatically mirror device. So you just installed SW RAID1 PReP and / boot is made only once 1 disk, the disk has twice the front part, you will not be able to secure a space to create a PReP partition separately.

There is a workaround for this problem. This method has been devised has rebooted successfully pulled jeongyuyoung behalf of Kolon, haebwado reboot after a number pulled out 1 disk in the test. Thanks to the efforts submitted jeongyuyoung behalf.

The following is the process of the workaround:

  1. Configure the Redhat installer, the OS mirror mdadm device except the PReP and boot in to.
  2. Remove the No. 2 in the completion of the OS installation disk mirror copy back mdadm to create a blank disk.
  3. Create a new partition, including the PReP and / boot to the same size as the one that emptied twice disk 1 disk.
  4. PReP of them as / boot, copy the text of No. 1 disk using the dd command.
  5. Remaining partitions for OS, add a mirror copy as a new mdadm command.

But if you do, if you have work to do to write something in the future ever / boot to haejwoya Although the content of 2 write as the dd command again on the second disk. As well as / boot has rarely happen write. Notget now gathered in more detail the contents of the above.

  1. Installed to configure a “/” and “swap” parts of the disk to mdadm device (ie SW RAID1). The PReP and / boot is excluded.
    – PReP Apart from beating, why / boot also andoeneunji Although the configuration has to wonder mdadm device.
  2. After completion of the OS installation, to remove the disk 2 in / and swap consisting of MD device through the OS command mdadm.

    # mdadm –manage / dev / md126 –remove / dev / sdb1 (swap area)
    # mdadm –manage / dev / md127 –remove / dev / sdb2 (/ area)

  3. Now empty the tongue twice a disc by using the same fdisk command with the # 1 partitioned disk.

    # fdisk -l / dev / sda ( 1 times the disk partition identify situations)
    # fdisk / dev / SDB (configure once in the same manner as disk partition, one partition on the second one disk obtained from the information above), especially at the front to make / dev / sdb1 in the disk type is 41 (PPC PReP Boot) to The haejwoya configuration.

    Fdisk # / dev / sda

    Command (Help for M): T
    Hex code (type L to the List Trade shows All codes): 41
    the Changed type of partition ‘Linux’ to ‘PPC PReP Boot’

    So the two as follows: create a disk partition to have the same information.

    Device Boot Start End Blocks Id System
    / dev / sda1 * 2048 18 431 8192 41 PPC PReP Boot
    / dev / sda2 18 432 1,067,007 524288 83 Linux
    / dev / sda3 1067008 9455615 4194304 82 Linux swap / the Solaris
    / dev / sda4 9455616 1875384319 932 964 352 5 Extended
    / dev / sda5 9,457,664 1875384319 932 963 328 8E Linux LVM

    Device Boot Start End Blocks Id System
    / dev / sdb1 2048 18 431 8192 41 PPC PReP Boot
    / dev / sdb2 18 432 1,067,007 524288 83 Linux
    / dev / sdb3 1067008 9455615 4194304 82 Linux swap / the Solaris
    / dev / sdb4 9455616 1875384319 932 964 352 5 Extended
    / dev / sdb5 9457664 1875384319 932 963 328 8E Linux LVM

  4. Configure the mirror / and the swap partition to mdadm command.

    # Mdadm –manage / dev / md126 –add / dev / sdb3 (swap area)
    # –manage mdadm / dev / md127 –add / dev / sdb5 (/ area)

  5. Copy the PReP partition by using the dd command.

    Dd the IF = # / dev / sda1 of = / dev / sdb1 bs = 1024K

  6. Boot Partition Copy the dd command. However, in this case, first create a new filesystem on the / boot, you must umount again and proceed with the existing / boot.

    First, make sure the existing / boot filesystem to create any type. Here are a xfs.

    # Mount | Boot grep
    / dev / sda2 on / type XFS Boot (RW, relatime, attr2, inode64, noquota)

    There format to make the same size you wrote / dev / sdb2 in response to a xfs. (This format superblock copy is downed by the andoe dd)

    # XFS mkfs -t -f / dev / sdb2

    Brings up the following must first dd and umount the existing / boot on. (superblock does not copy pops up a dd in the mount state.)

    # umount / Boot
    # dd the IF = / dev / sda2 of = / dev / sdb2 bs = 1024K

    Turning now look out into xfs_admin command / dev / sdb2 in / dev / has the same UUID and sda2 go. This uses the same UUID, you do not have to modify the /boot/grub2/grub.cfg bother. Because of this, there is also likely to be when the / boot to / dev / not sda2 / dev / sdb2 mount server boot, anyway, is not it the same copy will be almost no problem, write things happen there.

    Xfs_admin -u # / dev / sda2
    UUID = 20a94402-8589-48db-b8cf-e82c16f415ee

    # xfs_admin -u / dev / sdb2
    UUID = 20a94402-8589-48db-b8cf-e82c16f415ee

    and mount it look the same as the original file in / boot are look the same.

    : Mount # / dev / sda2 / Boot
    #: mount / dev / sdb2 / mnt

    # ls -l / Boot
    TOTAL 183 444
    -rw-r – r–. 138 001 Oct 17 2017 config root root 1-4.11.0-44.el7a.ppc64le
    drwxr-XR-X. Root root 17 May 30 2:58 p.m. the EFI 3
    drwx ——. Root root 118 May 30 17:11 5 grub2
    -rw ——-. 64932747 May 30 15:07 initramfs root root 1-0-rescue-168b61eb0f2d43cb8783c83d162b35f9.img
    -rw ——-. 44,154,461 30 May 17:11 initramfs root root 1-4.11.0-44.el7a.ppc64le.img
    -rw ——-. 22,527,454 30 May 15:27 initramfs root root 1-4.11.0-44.el7a.ppc64lekdump.img
    -rw-r – r–. 10,382,937 30 May 15:06 initrd root root 1-plymouth.img
    -rw-r – r–. Root root 250 055 Oct 17 2017 symvers 1-4.11.0-44.el7a.ppc64le.gz
    -rw ——-. 1 root root 2754018 Oct 17 2017 System.map -4.11.0-44.el7a.ppc64le
    -rwxr-xr-x. 21346760 May 30 15:07 vmlinuz root root 1-0-rescue-168b61eb0f2d43cb8783c83d162b35f9
    -rwxr-xr-x. 17 Oct 2017 vmlinuz root root 21.34676 million 1-4.11.0-44.el7a.ppc64le

    # ls -l / mnt
    TOTAL 183 444
    -rw-r – r–. 138 001 Oct 17 2017 config root root 1-4.11.0-44.el7a.ppc64le
    drwxr-XR-X. Root root 17 May 30 2:58 p.m. the EFI 3
    drwx ——. Root root 118 May 30 17:11 5 grub2
    -rw ——-. 64932747 May 30 15:07 initramfs root root 1-0-rescue-168b61eb0f2d43cb8783c83d162b35f9.img
    -rw ——-. 44,154,461 30 May 17:11 initramfs root root 1-4.11.0-44.el7a.ppc64le.img
    -rw ——-. 22,527,454 30 May 15:27 initramfs root root 1-4.11.0-44.el7a.ppc64lekdump.img
    -rw-r – r–. 10,382,937 30 May 15:06 initrd root root 1-plymouth.img
    -rw-r – r–. Root root 250 055 Oct 17 2017 symvers 1-4.11.0-44.el7a.ppc64le.gz
    -rw ——-. 17 Oct 2017 2754018 the System.map root root 1-4.11.0-44.el7a.ppc64le
    -rwxr-XR-X. 21346760 May 30 15:07 vmlinuz root root 1-0-rescue-168b61eb0f2d43cb8783c83d162b35f9
    -rwxr-xr-x. 1 root root 21346760 Oct 17 2017 vmlinuz -4.11.0-44.el7a.ppc64le

    if confirmed over / mnt umount you are and start using.
    # Umount / mnt

This will be the end of the OS mirroring.

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