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Instructions for switching to RAID 1 for XenServer 6.2 with GPT

Instructions for switching to RAID 1 for XenServer 6.2 with GPT

  • Create new partition for Local Storage
# gdisk /dev/sda
  • Check /dev/sda partition table
# gdisk -l /dev/sda
(...)
Number  Start (sector)    End (sector)  Size       Code  Name
   1            2048         8388641   4.0 GiB     0700
   2         8390656        16777249   4.0 GiB     0700
   3        16779264      1953525134   923.5 GiB   8E00
  • Check /dev/sdb partition table
# gdisk -l /dev/sdb
  • Create RAID partitions on /dev/sdb.

Replicate the partition table sectors. Choose fd00 as code for partition type.

The result should look something like this:

Number  Start (sector)    End (sector)  Size       Code  Name
   1            2048         8388641   4.0 GiB     FD00  Linux RAID
   2         8390656        16777249   4.0 GiB     FD00  Linux RAID
   3        16779264      1953525134   923.5 GiB   FD00  Linux RAID
  • Create MD devices
# mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sdb1 missing
# mdadm --create /dev/md1 --level=1 --raid-devices=2 /dev/sdb2 missing
# mdadm --create /dev/md2 --level=1 --raid-devices=2 /dev/sdb3 missing
  • Mount /dev/md0 and copy the filesystem to it
# mkfs.ext3 /dev/md0
# mount /dev/md0 /mnt
# cp -vxpR / /mnt
  • Modify /mnt/etc/fstab and change the root= parameter to /dev/md0. (Do NOT include the LABEL=)
# sed -i 's/LABEL=[a-zA-Z\-]*/\/dev\/md0/' /mnt/etc/fstab
  • Create a new boot image and uncompress it:
# mkdir /mnt/root/initrd-raid
# mkinitrd -v --fstab=/mnt/etc/fstab /mnt/root/initrd-raid/initrd-`uname -r`-raid.img `uname -r`
# cd /mnt/root/initrd-raid
# zcat initrd-`uname -r`-raid.img | cpio -i
# sed -i 's/raidautorun \/dev\/md0/raidautorun \/dev\/md0\nraidautorun \/dev\/md1\nraidautorun \/dev\/md2/' init
# rm initrd-`uname -r`-raid.img
  • Copy the new ramdisk to the /mnt/boot folder and modify boot menu
# find . -print | cpio -o -Hnewc | gzip -c > /mnt/boot/initrd-`uname -r`-raid.img
# rm /mnt/boot/initrd-2.6-xen.img
rm: remove symbolic link `/mnt/boot/initrd-2.6-xen.img’? y
# ln -s initrd-`uname -r`-raid.img /mnt/boot/initrd-2.6-xen.img
# sed -i 's/LABEL=[a-zA-Z\-]*/\/dev\/md0/' extlinux.conf
  • Set up MBR for GPT on /dev/sdb
# cat /mnt/usr/share/syslinux/gptmbr.bin > /dev/sdb
# cd /mnt
# extlinux  --raid -i boot/
  • Make sure the bootable flag is set on the partitions
# sgdisk /dev/sda --attributes=1:set:2
# sgdisk /dev/sdb --attributes=1:set:2
  • Unmount /dev/md0
# cd
# umount /dev/md0
# sync
  • Reboot ( IMPORTANT: Set your server to boot from the SECONDARY HDD before booting!)
# reboot
  • After the reboot is (hopefully) complete, it's time to switch /dev/sda's partitions to RAID
# gdisk /dev/sda
Press 't' select partition number and type in fd00.
Repeat for all your partitions. Then 'w' to write changes.

Your partition table should look something like this:

(...)
Number  Start (sector)    End (sector)  Size       Code  Name
   1            2048         8388641   4.0 GiB     FD00
   2         8390656        16777249   4.0 GiB     FD00
   3        16779264      1953525134   923.5 GiB   FD00
  • You are now ready to add these partitions into the RAID arrays
# mdadm -a /dev/md0 /dev/sda1
mdadm: added /dev/sda1
# mdadm -a /dev/md1 /dev/sda2
mdadm: added /dev/sda2
# mdadm -a /dev/md2 /dev/sda3
mdadm: added /dev/sda3
  • To check how the RAID sync is going look at:
# watch -n 1 cat /proc/mdstat
  • When it's done on all three arrays, copy the RAID setup to /etc/mdadm.conf
# mdadm --detail --scan >> /etc/mdadm.conf
  • At last add /dev/md2 as a local SR to XenServer
# xe host-list

uuid ( RO)                : 0f85df3a-52be-44b5-83cb-828cf1d1c6b2
          name-label ( RW): xenserver-joatnkwg
    name-description ( RW): Default install of XenServer

# xe sr-create content-type=user device-config:device=/dev/md2 host-uuid=0f85df3a-52be-44b5-83cb-828cf1d1c6b2 name-label="Local Storage" shared=false type=ext
  • You should now have a fully functional RAID 1 XenServer 6.2 Setup!
@rephapeng

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@rephapeng rephapeng commented Jul 20, 2014

what the different if I use
"cat /mnt/usr/share/syslinux/gptmbr.bin > /dev/sdb" and
"cat /mnt/usr/share/syslinux/mbr.bin > /dev/sdb" to create bootloader?

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