Проверено, работает. В отличии от статьи описнной на Citrix минимальное кол-во дисков 2 а не 3 и на рэйде не только SR но и сама система XenServer. Очень полезно при использовании на дешевых серверах с FAKERAID (например Intel Embedded RAID) Правда при загрузке в биосе показывает что рэйд DEGRADED. Кроме того можно использовать на любых серверах без рэйда вообще.

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Configure XenServer 5.0 Free for Software RAID 1

I used the notes from some guy on the Citrix forums. I wish that I had his name so I could give him credit but it’s not here on the stuff I printed out.

On with the show.

To make this work, you need to drives in your system. The second drive must be identical or larger than the first, and you must have installed XenServer to the first drive without selecting the second drive as part of the storage pool.

Install XenServer as usual. Do not select any extra drives as storage pools.

After installation, boot up, and login into console 3 (Alt-F3) as root

type fdisk -l to list the partitions:

Most likely your disks are represented by SCSI device names under linux / XenServer 5.0

in that case your boot disk would be /dev/sda,

To copy the partition table from /dev/sda to /dev/sdb you can use dd

dd if=/dev/sda of=/dev/sdb bs=512 count=1

Now set the partition table up on /dev/sdb the way it should be for Linux RAID. This means setting the partition types to 0xfd.

I used the following command:

echo -e "\nt\n1\nfd\nt\n3\nfd\nw\nx" | fdisk /dev/sdb

That tells says to fdisk, “tag partition 1 as type 0xfd, tag partition 3 as type 0xfd”

Check to make sure the /dev/md? devices are present

[ -e /dev/md0 ] || mknod /dev/md0 b 9 0
[ -e /dev/md1 ] || mknod /dev/md1 b 9 1

Startup the degraded RAID devices

mdadm --create /dev/md0 --level=1 --raid-devices=2 missing /dev/sdb1
mdadm --create /dev/md1 --level=1 --raid-devices=2 missing /dev/sdb3

The following procedure is directly from the other guys notes. I’ve modified the commands to what I think works a little better.

pvcreate /dev/md1
volume_group=`vgscan | grep VG | awk -F \" '{print $2}'`
vgextend $volume_group /dev/md1
pvmove /dev/sda3 /dev/md1

1. If this is a fresh install, then there won’t be any data to move

vgreduce $volume_group /dev/sda3

Now we’re ready to copy the filesystem over to the RAID device /dev/md0

mkfs.ext3 /dev/md0
cd / && mount /dev/md0 /mnt && rsync -a --progress --exclude=/sys --exclude=/proc --exclude=/dev/shm --exclude=/dev/pts / /mnt
mkdir /mnt/sys
mkdir /mnt/proc

sed -r -i 's,LABEL=root-\w+ ,/dev/md0 ,g' /mnt/etc/fstab

Now let’s setup initrd

mkdir /root/initrd && cd /root/initrd
zcat /boot/initrd-`uname -r`.img | cpio -i && \
cp /lib/modules/`uname -r`/kernel/drivers/md/raid1.ko lib

Now we have to edit the init file

q="echo Waiting for driver initialization."
sed -r -i "s,^${q}$,\n\necho Loading raid1.ko module\ninsmod /lib/raid1.ko\n${q}\n,g" init
q="resume /var/swap/swap.001"
sed -r -i "s,^${q}$,${q}\necho Running raidautorun\nraidautorun /dev/md0\nraidautorun /dev/md1,g" init
r=`grep mkroot /root/initrd/init`
sed -r -i "s|^${r}$|${r/sda1/md0}|g" init

Now we’ll copy the initial ramdisk to the /boot on the new RAID

find . -print | cpio -o -c | gzip -c > /mnt/boot/initrd-`uname -r`.img
sed -r -i 's,LABEL=root-\w+ ,/dev/md0 ,g' /mnt/etc/fstab
sed -r -i 's,LABEL=root-\w+ ,/dev/md0 ,g' /etc/fstab

And setup the boot loader

sed -r -i 's,root=LABEL=root-\w+ ,root=/dev/md0 ,g' /mnt/boot/extlinux.conf
sed -r -i 's,root=LABEL=root-\w+ ,root=/dev/md0 ,g' /boot/extlinux.conf
cat /usr/lib/syslinux/mbr.bin > /dev/sdb
cd /mnt && extlinux -i boot/
extlinux -i boot/

If you’ve done this remotely, you can try the following.

cp /mnt/boot/extlinux.conf /boot/
cp /mnt/boot/initrd-`uname -r`.img /boot

Unmount /dev/md0, sync, and reboot

cd ; umount /mnt || umount /dev/md0
sync
reboot

First we tag the partitions as type Linux raid, then we have to add /dev/sda to the RAID.

echo -e "\nt\n1\nfd\nt\n3\nfd\nw\nx" | fdisk /dev/sda
mdadm -a /dev/md0 /dev/sda1
mdadm -a /dev/md1 /dev/sda3

Troubleshooting

The first time I did this procedure I got stuck because my rsync didn’t copy /proc and /sys like I asked it not to. So I had to add the step of creating those two directories so they could be mounted at boot.

After messing around with it a little, I came up with this command line to boot XenServer 5 from extlinux.

mboot.c32 /boot/xen.gz dom0_mem=752M --- /boot/vmlinuz-2.6-xen root=/dev/md0 single --- /boot/initrd-2.6-xen.img