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Old January 5, 2011, 11:46 AM
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Quote:
Originally Posted by Empty_Quarter View Post
The RAID controller (onboard software or hardware) will tell upon boot which drive is dead, usually by the drive's ID (that the manufacturer gave it, not what you put in windows).

If a HDD does die, you replace it, and the raid controller will use parity data on the remaining drives to build the new drive. The quality and speed of the rebuilding process is Dependant on your controller.

In raid 5, whatever number of drives you have, you lose 1 drive, so n-1. In raid-6, you lose 2 drives.
Ok I'm getting it now, I thought with raid6 you just were allowed to loose 2 drives instead of 1? Example,
If I had 3 Hard drives in raid 5 and lost one I need to replace it asap before I loose another,
If I had 4 Hard drives in raid 6 and lost one I would be ok but if I lost 2 I would need to replace them asap before I lost a third.
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Old January 5, 2011, 11:49 AM
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Quote:
Originally Posted by Blu View Post
Ok I'm getting it now, I thought with raid6 you just were allowed to loose 2 drives instead of 1? Example,
If I had 3 Hard drives in raid 5 and lost one I need to replace it asap before I loose another,
If I had 4 Hard drives in raid 6 and lost one I would be ok but if I lost 2 I would need to replace them asap before I lost a third.
You got it, however it's still recommended to replace right away.
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Old January 5, 2011, 12:11 PM
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Quote:
Originally Posted by Blu View Post
Ok I'm getting it now, I thought with raid6 you just were allowed to loose 2 drives instead of 1? Example,
If I had 3 Hard drives in raid 5 and lost one I need to replace it asap before I loose another,
If I had 4 Hard drives in raid 6 and lost one I would be ok but if I lost 2 I would need to replace them asap before I lost a third.
Yep, pretty much.

This is also where a hot-spare drive comes into play. A hot-spare drive is as the name implies a spare drive that the controller will use to rebuild if a drive dies. So if you have 4 1TB drives, places 3 in RAID-5 which gives you 2TB worth of space. In the event a drive does die, the controller will immediately start rebuilding the content of the lost drive on the spare drive.
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Old January 5, 2011, 01:03 PM
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Originally Posted by Empty_Quarter View Post
Yep, pretty much.

This is also where a hot-spare drive comes into play. A hot-spare drive is as the name implies a spare drive that the controller will use to rebuild if a drive dies. So if you have 4 1TB drives, places 3 in RAID-5 which gives you 2TB worth of space. In the event a drive does die, the controller will immediately start rebuilding the content of the lost drive on the spare drive.
And I'm assuming the software with the raid controller would alert me of the drive failure and of the rebuild?
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Old January 5, 2011, 08:52 PM
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the Raid Management software will alert you, if installed and configured properly. Note that the device driver alone will NOT alert you of a drive failure, or if an inconsistency is discovered during a data integrity check.

I don't know what the hell Empty_Quarter is talking about, thinking raid 10 is a poor performance solution for redundancy. In practice it performs better than RAID 5. One of my multinational IT clients is migrating all of it's Microsoft Exchange 2007 cluster farms from RAID 5 to RAID 10 because of it's performance boost to the I/O subsystem (dramatic when you have tens of thousands of mailboxes).
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Old January 5, 2011, 09:18 PM
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Quote:
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I've heard from people that raid 5 will protect all your data on both drives but how exactly?
It installs google into your BIOS(or RAID controller card) and uses magic. (actually all your data is sent to google and the FBI for their records)
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Old January 6, 2011, 05:08 AM
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Quote:
Originally Posted by grinder View Post
I don't know what the hell Empty_Quarter is talking about, thinking raid 10 is a poor performance solution for redundancy. In practice it performs better than RAID 5. One of my multinational IT clients is migrating all of it's Microsoft Exchange 2007 cluster farms from RAID 5 to RAID 10 because of it's performance boost to the I/O subsystem (dramatic when you have tens of thousands of mailboxes).
I never said RAID 10 was a bad solution, what I meant was this: First, for RAID 10 to work, you dont need a hardware raid card as opposed to RAID-5, 6, 50, etc... as it does not use parity bits for redundancy to work, so it can work on any software onboard RAID solution just fine. Second, while RAID 10 is as flawless as it gets for protection, its an inefficient solution as you lose half the drives you have (Compared to RAID-6 where you lose just 2 drives and get just as anal protection).

If you have 10 Drives and use RAID-10, you have 5 drives worth of space.
If you have 10 Drives and use RAID-6, you have 8 drives worth of space. Sure, you do need to factor in the cost of a 10+ hardware raid-6 card.

So if you use RAID-10 for anything higher than 4 drives, there is nothing wrong with it, you are just losing more space than you would with other RAID solutions.
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