Bad drive in RAID configuration.

Hello Experts,

I have a server that has two HDD that I believe I setup both as either a RAID 1 OR RAID 0 if that makes any sense for the Operating System that runs Windows 2008 R2.

My Client just called me to tell me that one of those two drives has a red light next to it. The drive is an HP 300GB SAS 10,000 RPM HDD.

I have replaced HDD's in a RAID 5 before were you just put the drive back in and it builds back up. But do I need to do anything special for a HDD in a RAID 1 or 0 for an OS or do I just simple plug it in and let it build back up again?
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If its RAID1 its simple - pull drive and insert new drive and it 'should' start the rebuild - what model server?

If its RAID0 - well it can't be as a failed drive in RAID0 will kill the entire array, so must be raid1

Red light might mean different things though - is this a branded server like HP/Dell?
PowerEdgeTechIT ConsultantCommented:
Well, if it is a RAID 0, you can't replace a drive without data loss - you would need to pull out your backups or reinstall.

If it is a RAID 1, yes, you can just pull it out and replace it, and in most cases, the controller will begin a rebuild on it.

What system and controller model do you have?
asp_net2Author Commented:
I just spoke to my client and he said that he can still access the server and the data on the drive. So would that mean RAID 1 or 0? I'm not at his office now, I know that sounds bad but he is not there an he will not be there until tomorrow. So, not sure what to do or plan for before tomorrow. I don't recall of the top of my head the name of the Array Controler. I know it's something like SMart Array P410i or something like that.

The server is HP ProLiant ML350T06 Server.
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It has to be RAID1 if it is still running - bar that red light is a warning rather than a failure...

Smart array controllers usually initiate the rebuild themselves once the drive is swapped
If it doesn't then you will need to access the controller and assign the new drive as a 'hot spare' to kick start the process...

Make sure its a blank unused drive you insert as if it had data on it the rebuild will not kick automatically

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It is entirely possible you have BOTH RAID0 & RAID1.  Don't make any assumptions.  HP has a  program (ACU) that will report details on the configuration and health. You can go to the and just download a bootable CD, or windows, linux, and other versions depending on what customer is using.

It just isn't worth the risk of making assumptions, especially in situations where end-user doesn't know what he has, and you can download utility programs that will tell you everything w/o having to guess.

P.S. The SMART START CD image has PDF manuals that walk you through what to do based on the LEDs and what the ACU program tells you about the config.  Too many possibilities to just give you all possible answers.
asp_net2Author Commented:

What would I do if the HDD is BOTH RAID0 & RAID1?
Based on what you said - 'server has 2 HDD' it has to be EITHER 0 or 1 - if you have 4 drives then yes you could have BOTH RAID0 and 1...but with only 2 drives its one of the other...
PowerEdgeTechIT ConsultantCommented:
You said "you" set this up.  If that is the case, and you aren't sure the difference between RAID's 0 and 1, then you would not have configured both.  It is MOST likely a RAID 1 with a single failed drive.  Sure, assumptions are bad, but let's be sensible.  Worried?  By all means install the HP software (or boot to the controller's BIOS utility) to confirm.
asp_net2Author Commented:

Ok, thank you. Yes, it's only two HDD's for the OS. The rest of the drives I have configured as a RAID6.

I'm going to keep this post open until tomorrow evening for additional help that I may need once I actually have my hands on the server. Is there something I need to look for that would tell me that I need to remove/install the Array rather than plugging the HDD back in to have it rebuild?
The ACU @dlethe mentioned, or check the server for anything installed under the HP Array section(usually on the Start menu somewhere)
You can have both a RAID1 and a RAID0 if the pesky end-user decided they wanted to incorporate O/S-based RAID1 or RAID0, or anything else by partitioning the logical volume the RAID presented to the O/S.

Don't eliminate the possibility that the RAID controller has exclusivity to being the only method of configuring RAID.  Or you could have 2 single disks now at RAID0 by the controller, and the user decided to break up those 2 individual RAID0 drives and built any combination of RAID0,1, or even built multiple partitions and turned that into a host-based RAID5.  

Doubtful, but that is why you don't just assume you know the config on any system that hasn't been under your control.
andyalderSaggar maker's framemakerCommented:
Smart Array controllers do RAID at the logical disk level rather than at the array level so it is possible to have both a RAID1 logical disk and a RAID 0 logical disk on an array of just two disks. If you had 4 disks you could even have a combination of RAID 0, 10, and 5 on them.

Pretty unlikely though as the default during install is a single RAID 1.

Rebuild is automatic so long as you replace the disk hot, do not replace it with the power off since that can lock up the controller.
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