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ML330G3 - ATA RAID operations - OS upgrade scenario

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Ranieri Almeida
Occasional Visitor

ML330G3 - ATA RAID operations - OS upgrade scenario

Our ML330G3 is equiped with the following 3 drives:

I - ATA drive with OS and applications
II - ATA drive, mirrored from drive I through RAID-1
III - SCSI drive with data

We are looking to perform an OS upgrade and our strategy is the following:

1 - Disable RAID configuration
2 - Perform clean install on drive II
3 - Configure OS and apps, and if everything tests ok, enable RAID configuration with drive I now mirrored from drive II

Installation and configuration is being simulated in a lab. The problem is that we have no experience performing RAID operations. The documentation we found is limited and appears to imply that disabling RAID will cause immediate loss of data from both drives. We are confused. How do we go about carrying out our upgrade strategy? Where can we find more thorough documentation? Hopefully the answer to these questions will help us know what to do in a recovery scenario as well.
Honored Contributor

Re: ML330G3 - ATA RAID operations - OS upgrade scenario

First, I think what you read is misleading. If you were to go into the RAID setup and delete the RAID set, The data may get effected depending on what the controller does at the time of deleting the RAID set info. For a RAID 1, this may not be true, but for a RAID 5 it is definately true, so there in lies the confusion.
Breaking the RAID is another matter, i.e. removing on of the drives in the RAID 1 set. This will cease the RAID function, but leave the SSet info intact, with function returning when the set drives are back to the original numbers. I think this is what you wish to accomplish.

Now, my question would be about why you have the architecture you have, mirroring the OS and not the data. To me this is backwards, a simple ghost or backup of the OS drive would keep your new install and configuration clean from corruption and give you a restore point in the OS should fail, while mirroring the data keeps your data always available even if a drive should fail.
We never recommend a mirror of a Windows OS due to the high disk usage of Windows. The RAID controller is working overtime just to keep up with all the Windows reads and writes, not to mention all the temporary data. We actual would setup up a RAID 1 on 4 drives, 2 for the OS and 2 for the data, then break the OS RAID and keep the clean set member offline for a backup and quick swap in if a restoation is needed of the OS.
Just my thoughts.
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Ranieri Almeida
Occasional Visitor

Re: ML330G3 - ATA RAID operations - OS upgrade scenario

Thank you very much for the repply. You are absolutely right about we having it backwards. You are also right about what we are trying to do. We are newbies here working with a setup from another newby...

At any rate, here is our updated strategy, given that the drives have the required capacity:

- For safety, build image of RAIDed OS drive, in this case drive I.
- Quick format drive I and transfer data from the data disk (drive III) to drive I (Without any change in RAID configuration, which means data will be transfered to both RAID-1 drives)
- Install new OS on drive III (Leaving the OS on the non-RAID drive)

Which should leave us with the following drive configuration:

I - Drive in the unchanged RAID configuration, only now it contais data and not the OS
II - Mirrored RAID drive, now with a copy of the data
III - Non-RAID OS drive

Will this work?

Also, if we get another drive to RAID the OS as well: Just add the drive, run the RAID configuration utility to add it, and then remove it again if we want to keep it offline. Correct?