Ghost Nightmares. RAID5 to RAID1.

[Vini]

I'm having a Ghost Nightmare.

We've a server, with 4 drives, in Raid 5. Offering 200gb of space. This 200gb is partitioned into two; 10gb + leftover.

Our OS Partition (10gb) is down to 500mb free, obviously due to a schoolboy error when it was initially configured...

This server is stateside, which is where I am until Friday.

I've taken an Image of the Boot partition and restored it to two new drives in RAID1. Testing back in the UK said this should work without a problem. Of course, nothing runs smoothly when Live.

Upon restoring the image of the Boot partition and rebooting, the server says it cannot boot from the HDD's.

Is this a RAID5 > RAID1 issue?

Short of running GParted and fiddling with the partition sizes that way, what options can you folks offer me...

[arthurleung]

It shouldn't make any difference. Your RAID card should handle all underlying communication to hardware and the partition doesn't need to know whether it is part of RAID or not.

How did you build that RAID in the first place? Is it hardware RAID or software?
RAID, software or hardware card, requires you to install a driver to work. If the driver is not already installed you cannot boot from it, presumably you moved to another controller.

[Splash]

What Arthur says - a proper RAID should be invisible to the OS.

[peterb]

You didn't sat what OS you are using. If you are using mdadm on a Linux system, the boot partition cannot be part of the RAID array - because the kernel needs the RAID driver to read the drives. This is overcome by having a kernel image containing the driver on the boot partition which is loaded into memory first, then the array becomes visible to the OS, which then loads normally.

However from what you aid, you did have this set up running correctly on a development set up in the UK, so it is likely to be a configuration error. I also see that you have a 500Gb OS partition, which seems small to me unless you are using a stripped down OS.

[aidanjt]

If you are using mdadm on a Linux system, the boot partition cannot be part of the RAID array - because the kernel needs the RAID driver to read the drives.

Actually, /boot can be on a MD RAID1 partition, the actual limitation to having /boot on other RAID modes is lack of grub support for them, if grub could read RAID5, it will load the kernel and initramfs into memory and proceed.

[Vini]

It's server 2003...

[Vini]

I redid the Image, Recreated the RAID and restored the image.

2nd time lucky.

Relieved man.