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RAID Mirroring and Losing Data

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  • NAS / RAID
  • Storage
Last response: in Storage
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April 5, 2013 8:46:09 AM

Motherboard z77x UD3H
2 x 1TB Western Digital with RAID mirroring set up at the motherboard level.

I had issues reinstlaling Windows 7 last week. I googled and was told that when I boot from the Windows 7 Home Premium disk it has issues installing if any other drives are connected to the motherboard. (I do not have this issue if I boot up from a hard drive and then run an install).

The note suggested I disconnect my other drives. These others were RAID Mirroring. Instead I went to the bios and went to 'boot options' and disabled my RAID mirroring drives. This broke the RAID.

This is what happened.
1. One disk was listed as not formatted at all with nothing on it
2. Other disk had some really old data on it. When the system was delivered to me, my windows SSD boot drive could not see the RAID and I had to do something in DISK Manager to see it (I forgot what I did). The data on the disk is from before I did that.

Any idea what happened? I had a RAID Mirroring Disk set break once in an older motherboard due to the motherboard battery dying. All the data was on both disks. If I am going to lose data just because the RAID Mirroring breaks (a motherboard battery could die on me again), what is the value of mirroring in a home system?

I do keep backups on external drives. However, I use my SSD for boot and then install all software to my RAID disks since I have more space.

More about : raid mirroring losing data

April 5, 2013 8:48:42 AM

I read this:

http://www.tomshardware.com/forum/259807-32-raid

In my motherboard RAID configuration or BIOS I don't see a way to adjust the RAID Mirroring level. I don't know what it gives me, but I basically want whatever is least likely to lose data. I don't care if its a little slower. I just use this for internal backups and to install software. It is just for home use.

Yes I have external backups also.
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a b G Storage
April 5, 2013 9:03:46 AM

For home use, RAID is pretty much overkill. The main goal, is to reduce down time when catastrophe strikes. In a production environment, it is a necessity - as down time costs the business money.

At work, most of my configurations are RAID 10. At home, I do not use RAID, I have an OS drive (SSD), data drive (1 TB WD Black) and a backup drive for my entire network (2 TB WD Black). I use SyncBack Free ( http://www.2brightsparks.com/download-syncbackfree.html ), and run a nightly batch to backup my drives. The best part of using this software, it doesn't delete files that I have deleted, I have 100% of my data, and with a simple copy, I can put it back - RAID doesn't do that.

The only reason to use RAID at home would be in the case where there is no other way to create a volume size that is needed for a purpose (i.e. Windows Media Center TV recording must be a single drive, and if you need a ton of space, you must use RAID).

You will have more headaches that pleasant experiences using RAID.

In the production environment, when ANY change is made to RAID arrays - first process is a 100% backup prior to the changes - because "IT" will happen.
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April 6, 2013 8:57:20 AM

This is not an answer to the question I asked. Why am I losing data when a RAID mirror breaks? I Have had a motherboard battery break and my raid broke. all data was on both drives.
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a b G Storage
April 8, 2013 7:35:44 AM

Are you using software or hardware RAID to configure the array?
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April 16, 2013 10:16:14 AM

hardeware. set it up in the bios. the original raid mirror was setup for me. I am wondering if they did it wrong.
1 drive is showing as not formatted.
2 other dirve had some very old data on it. When i first go the PC, I could not see the RAID drive. I had to go to windows and assign a drive and sometihng else. itihnk the data I can see is before I installed all the drivers and configured with windows. It is from a year ago, so I don't remember.

The RAID mirror was configured in the bios. I have done it again. Reformatted. I want to make sure I don't have this problem again. If the RAID breaks the data should be present on both drives.

So went to ud3h bios. Turned on raid. went to raid configured. Picked my 2 drives for mirroring. It set up the RAID and wiped all data.

Then I booted off another drive. I partitioned my hard drive. Gave 50 GBs for a windows 7 install and formatted the rest to use for storage. booted off of my windows 7 drive and installed windows on the 50 GB partition. Went into Windows disk manager and assigned the drive.

Generally I boot off of a flash drive, but I want a boot partition on the RAID device in case I have issues with my other drive. so I can boot up and diagnose.

I don't know alot about RAID configuration. Do you think I missed anything? After configuring for RAID, I went back into the bios and set from RAID to DHCI. (manual said to do this).
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a b G Storage
April 16, 2013 12:53:39 PM

RAID has slightly different procedures for rebuilding an array when you lose a drive. RAID should not be used as a replacement for backing up your data. I would get the ud3h bios manual and determine the process for rebuilding the array when the drive dies. Some are as easy as removing the bad drive, installing the new drive, then entering BIOS and telling it to rebuild the array. Others are a bit more complex.

I would start up a "binder" to keep important documentation like rebuilding the array if it happens again.
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