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2TB Limitation

Last response: in Storage
November 14, 2008 9:45:28 AM

I have a Gigabyte X48-ds4 mb with 5-1tb drives. My intent was to use 1 TB as my primary OS drive, then run the 4-1TB drives in a raid5 setup. I have that setup fine but when i load up disk management in Vista Ultimate 64bit, it shows me Disk1 2048GB unallocated space then another 700gig of unallocated space. I can format the 2tb section and vista sees it fine but then i cant do anything with the remaining 700gig? is this normal?

I was hoping to run parity Raid5 and utilize all the space even if its in 2 partitions.

if that's not possible ill just run raid10 and get 2TB striped. Any idea if i can run raid5 and utilize all the space?

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a b G Storage
November 14, 2008 10:00:39 AM

This document may make things clear. Basically, there is a 2TB limit to a Basic disk or to a Simple volume on a Dynamic disk. The document also explains how you can circumvent this limit.

(Note - although the document says that this limit does not apply to a RAID-5 volume, and you are using RAID-5, it is referring to software RAID, not hardware RAID.)
November 14, 2008 10:13:52 AM

Thanks Much iJack ill head off to read it and let you know how i make out.
Related resources
November 14, 2008 10:22:35 AM


I read the tech note and im somewhat confused (no surprise :)  ) it states:

Use basic disks if:

* You do not need to create volumes that exceed 2 TB.
* You are configuring shared cluster storage on a server cluster.
* The server runs other operating systems that cannot access dynamic disks. The only server operating systems that can access dynamic disks are Microsoft® Windows® 2000 Server and Windows Server 2003.

Use dynamic disks if:

* You want to create RAID-0 volumes or fault-tolerant volumes (RAID-1 or RAID-5) and the server does not contain hardware RAID.

Problem is my system uses hardware raid, so does this mean i cannot extend that volume to a larger size?
a b G Storage
November 14, 2008 10:30:31 AM

I think that what you have to do is:

1. (Assuming your hardware lets you) Define two logical arrays, both less than 2TB. These will appear to Disk Manager as two physical disks.

2. Using Disk Manager make these two disks Dynamic disks.

3. (Still using Disk Manager) Define a Spanned Volume that uses both of these disks.

4. That Volume will then appear to Windows as a single partiton using the total disk space.

Alternatively, you can just use the two logical arrays as separate disks.
November 14, 2008 11:52:19 AM

I will give it a shot and se how it goes. Ill post my results.

Thanks ijack
November 14, 2008 2:04:41 PM


Are you using Windows' RAID software? Or are you using the RAID controller on your motherboard? If you're using the one on the motherboard, you set that up in BIOS after POST. If you're just pushing in drives, loading windows, and saying "let's do RAID5" then that's your problem.

If you're using hardware (not windows software base) RAID, you won't have this issue.