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Cloning a SATA RAID 1 array over to a SAS RAID array?

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October 13, 2009 4:27:11 PM

I have a domain controller that is fast running out of space. Also, I would feel better if it had some brand new faster drives in it as we are getting write bottlenecks.

I was thinking cloning the RAID 1 SATA 2 based array over to a new RAID 1 SAS array. The SATA 2 array is based on an onboard controller, but the SAS would be on an external PCI express X1 controller card.

What is the easiest and most straight forward way to clone as outlined above? Keep in mind I want to keep the original array 100% intact incase I have to fall back to it in an emergency as this is my DC;)

Can I simply setup the new array, boot into windows via the old array, point something like Acronis to copy active array over to new array and change the partition ratios accordingly to account for the drive capacity difference? Or do I need to break the Array and copy one of the older pair drives to one of the newer pair drives using some other method? IE external drive cloning hardware ($$$) or can I hook up a SATA drives to one of the ports on the SAS controller, while having one of the new SAS drives on the other port? I have not done this before, so steps in point form would be appreciated.

I have Acronis Easy Migrate 7 and Norton Ghost. I will likely use Acronis, as I find Ghost relatively convoluted.

Thanks for the help,


a c 127 G Storage
October 13, 2009 9:06:39 PM

You can copy the raw disk contents (including all partition table and RAID configuration sector) to the new drives and the RAID engine shouldn't know what happened. Some may have nasty data in the configuration data though, like capacity. But its worth a try.

The problem here is, your new disks should be at least as large as your old disks. If they are, go connect the two source drives (current RAID1) to a plain controller without RAID or disable RAID mode in the BIOS and boot an Ubuntu or BSD livecd.

Then, copy the raw disk contents from one disk to another:

1) copy source disk 1 (SATA) to destination disk 1 (SAS)
2) copy source disk 2 (SATA) to destination disk 2 (SAS)

First you should know what your disks are labeled, once you booted a livecd, open a terminal and look at the output of:

# ls -l /dev/sd*

You should see your disks here; determine which is which because you should not make a mistake here! I'm assuming /dev/sda is SATA1 and /dev/sdb is SATA2; your two current RAID1 disks. sdc and sdd are your SAS disks in this example:

// copy raw contents of SATA disk1 to SAS disk1
sudo dd if=/dev/sda of=/dev/sdc bs=1M

// copy raw contents of SATA disk1 to SAS disk1
sudo dd if=/dev/sda of=/dev/sdc bs=1M

make sure you do not make mistakes with the command, if= is the read device, of= is the write device. Before doing this you might want to create a backup in case something happens to your data.
a c 127 G Storage
October 13, 2009 9:08:07 PM

Still cannot edit my posts, the second command was copy-pasted but not changed, it should be:

// copy raw contents of SATA disk1 to SAS disk1
sudo dd if=/dev/sda of=/dev/sdc bs=1M

// copy raw contents of SATA disk1 to SAS disk1
sudo dd if=/dev/sdb of=/dev/sdd bs=1M

So sda is copied to sdc and sdb is copied to sdd. After this, connect the new SAS disks as usual. You may need to setup the RAID1 again if the metadata format differs. But it should work. :) 
!