Unable to format RAID5 volume as Basic Disk?

Collapse -

How To Establish a Striped Volume with Parity (RAID-5) in Windows Server 20

by Peconet Tietokoneet-217038187993258194678069903632 · 14 years ago In reply to Unable to format RAID5 vo ...

SUMMARY
A striped volume with parity, which is also called RAID-5 in Windows Server 2003, combines areas of free space from multiple hard disks (from 3 to 32) into one logical volume.

Parity is redundant information that is associated with a block of information. In products in Windows Server 2003, parity is a calculated value that is used to reconstruct data after a failure. RAID-5 volumes stripe data and parity across a set of disks. When a disk fails, Windows Server 2003 uses the parity information to re-create the data on the failed disk.

Because of this fault tolerance, administrators favour using RAID-5 volumes when data integrity and data input/output speed are both important. RAID-5 volumes cannot be mirrored, and they cannot be extended. Any file system can be used on a RAID-5 volume, including the FAT file system, the FAT32 file system, or the NTFS file system.

NOTE: Your operating system and boot files cannot reside on the RAID-5 disks. However, you can put the system swap file on a RAID-5 volume.

Requirements
?
A minimum of three hard disk drives. IDE, SCSI or mixed architecture is permissible.
?
All disks involved in the RAID-5 volume must be dynamic disks.
?
Operating system boot and system files must be on a different volume.

How to Set Up the Disk Management System
1.
Click Start, point to Administrative Tools, and then click Computer Management.
2.
Click the plus sign (+) next to Storage to open the Storage console tree.
3.
Click the Disk Management folder.
4.
On the View menu, point to Top, and then click Disk List. In the right pane, a column listing the attributes of each disk in the system is displayed.
5.
On the View menu, point to Bottom, and then click Graphical View.

A colour coded graphical view of the disks on the system is displayed.
The Disk Description pane (that is displayed in gray) is on the left side of the volume description that is displayed in colour. The disk description contains information about each disk's disk number, whether it is a basic or dynamic configuration, its size, and its status (online or offline).

The volume descriptions are colour-coded. They hold information on each volume such as the drive letter (if assigned), whether it is allocated or unallocated, the partition or volume size, and the health status of the volume.

How to Make Sure That Disks Are Set Up to Support RAID-5
?
Disks: You must have a minimum of three disks to support striping.
?
Type: Any disks involved in striping must be dynamic. Conversion from basic to dynamic goes very quickly without data loss. After you complete this procedure, you must restart the computer.
?
Capacity: The RAID-5 volume can take the whole disk or as little as 20 megabytes (MB) for each disk.
?
Unallocated space: Any disks that you want to upgrade to a dynamic disk must contain at least 1 MB of free space at the end of the disk for the upgrade to succeed. Disk Management automatically reserves this free space when it creates partitions or volumes on a disk, but disks with partitions or volumes that are created by other operating systems might not have this free space available.
?
Status: The status of all disks involved in a stripe volume must be online when you create the striped volume.
?
Device Type: You can install striping on any dynamic disk even if there are mixed drive architectures on the computer. For example, IDE, EIDE, and SCSI drives can all be used in one stripe volume.

How to Upgrade to Dynamic Disks
If the disks that are going to be involved in the stripe volume are already dynamic disks, skip this section and go to the next section ("How to Convert to Stripe Volume").

NOTE: You must be logged on as an administrator or a member of the Administrators group to complete this procedure. If your computer is connected to a network, network policy settings may prevent you from completing this procedure.

To upgrade a basic disk to a dynamic disk:
1.
Before you upgrade disks, quit any programs that are running on those disks.
2.
Right-click the gray Disk Description pane that is located to the left of the color-coded volume panes, and then click Upgrade to Dynamic Disk.
3.
If the second disk in not a dynamic disk, follow the steps earlier in this article to upgrade it to a dynamic disk.

How to Convert to RAID-5
In this scenario, there are four disks on the computer: Disk 0 , Disk 1, Disk 2 and Disk 3 . Disk 0 is reserved for the operating system and boot files because they cannot reside on a RAID-5 volume. The other three disks are the RAID-5 disks. There is 1 gigabyte (GB) of free unallocated space on each disk to commit to the RAID-5 volume.

NOTE: 1 GB of free space on each of the three disks gives you a total usable volume of 2 GB because of parity information that is written as part of each stripe.
1.
In the Disk Management tool, right-click the unallocated space on one of the dynamic disks where you want to create the RAID-5 volume, and then click Create Volume.
2.
After the Create Volume Wizard starts, click Next.
3.
Click RAID-5 volume, and then click Next.
4.
Click the disks in the left pane under All Available Dynamic Disks, and then click the Add tab.

The disks that are displayed in the right pane are labeled Selected.
5.
Look at the bottom of the Select Disk dialog box under the Size label.

The For All Selected Disks box displays the maximum size of the RAID-5 volume that you can make.

NOTE: The volume on each disk is the same size in the completed RAID-5 volume. For example, if you have 100 MB on the first disk, you have 100 MB on the second disk. You can reduce the size of the volume from the maximum size that the wizard automatically shows. To do so, click the arrow on the Disk Size box to lower the volume size on this disk. On a three-disk system, the total RAID-5 volume storage size is double the size that you enter here. The Total Volume Size box lists your total storage space.
6.
Click Next. At this time, you may want to assign a drive letter (you can also do this at any other time). To do so, click Assign Drive Letter, and then enter an available drive letter.

Alternatively, you can click Do not assign drive letter or path. You can also click Mount this volume on an empty folder that supports drive paths. However, this selection is beyond the scope of this article.
7.
Click Next.
8.
Click Format this partition with the following settings, and then follow these steps:
a.
Type the file system type; FAT32 or NTFS is acceptable.
b.
Leave the default selection in the Allocation Unit Size box.
c.
In the Volume Label box, you can keep the default "New Volume" label or you can type your own label.
d.
At this time, you can click to select the Quick Format check box and the File and Folder Compression check box. You can also defer both of these tasks if you like.
9.
Click Next, check your selection in the Summary window, and then click Finish.
The RAID-5 volume is displayed on the three disks on your system. They have the same color code, the same drive letter (if you mapped the drive during the procedure), and they are both the same size. If you clicked the Quick Format option, the status of the disks is displayed as "Regenerating" while the drives are being formatted. After the disks are formatted, the status of the disks is displayed as "Healthy". The RAID-5 volume is ready to be used; you do not have to restart the computer.

Troubleshooting
?
Never use a hardware-RAID solution and software RAID on the same disk.
?
Operating system files and boot files cannot reside on the RAID-5 disks.
?
Microsoft recommends RAID-5 over mirrored volumes for programs that require redundancy and are primarily read-oriented. Write performance is reduced by the parity calculation. Also, a write operation requires three times more memory than a read operation during typical operation. This condition is caused by the parity calculation.
?
RAID-5 volumes provide fault tolerance at a cost of one additional disk for the volume. This means that if you use three 10-GB disks to create a RAID-5 volume, the volume will have a 20-GB capacity. The remaining 10-GB are used for parity.
?
RAID-5 volumes cannot be extended or mirrored.
http://support.microsoft.com/kb/323434

Please post back if you have any more problems or questions.

Collapse -

Re: Striping (Raid5) and Dynamic Disks

by bwiedor · 14 years ago In reply to How To Establish a Stripe ...

Thank you, but there is something that I am not clear on.

The comment of "Type: Any disks involved in striping must be dynamic." does seem to imply the cause of the original problem, however:

We have a Windows 2003 cluster set up using 2 Dell PE1950s, 2 Brocade SW200E fiber switches, and a Dell/EMC2 AX150 disk array. I checked on our cluster, and the disks are basic there. As far as I can tell, the AX150 array is striped, since it allows for hot swapping and replacement of failed drives. Why, then, would it function with Basic disks, as I see in Windows 2003 Server for them?

Or does the EMC2 operate differently to avoid this issue?

Collapse -

This is a bit of information about both,

by Peconet Tietokoneet-217038187993258194678069903632 · 14 years ago In reply to Re: Striping (Raid5) and ...

And what you can do on one but not the other.

Basic disks use normal partition tables supported by MS-DOS and all Windows versions. A basic disk contains basic volumes, such as primary partitions, extended partitions, and logical drives. If you have any volume sets, stripe sets, mirror sets, or stripe sets with parity, you must back them up and delete or convert them to dynamic disks before you install Windows XP Professional. A basic or dynamic disk can contain any combination of FAT16, FAT32, or NTFS partitions or volumes. The disadvantage of a basic disk is that you are limited to creating only four primary partitions per disk or three primary partitions and one extended partition with logical drives. Windows NT based systems can support striping and software RAID sets for basic disks but Windows 2000/XP/2003 do not.

Dynamic disks are supported in Windows XP Professional, Windows 2000 and Windows Server 2003. Dynamic disks do not use partitions or logical drives. Dynamic disks were first introduced with Windows 2000. With dynamic disks you can create volumes that span multiple disks such as spanned and striped volumes, and you can also create fault tolerant volumes such as mirrored volumes and RAID 5 volumes. Dynamic disks offer greater flexibility for volume management because they use a database to track information about dynamic volumes on the disk and about other dynamic disks in the computer. Windows Server 2003 can repair a corrupted database on one dynamic disk by using the database on another dynamic disk. With dynamic storage, you can perform disk and volume management without restarting Windows.

Dynamic disks are not supported on laptop computers or on computers with Windows XP Home Edition installed. The number of volumes that you can create on a dynamic hard disk is only limited by the amount of free space available. Windows XP Pro, Home or 64 Bit Edition does not support mirrored or RAID5 volumes.

You can use both basic and dynamic disks on the same computer system.

To convert a Basic Disk to a Dynamic Disk:
It?s easy to convert a basic disk to a dynamic disk in Windows XP/2000/2003.

*
You must log in as an Administrator or as a member of the Administrators group.
*
Right click My Computer and select Manage
*
Click on Disk Management
*
Right click the basic disk that you want to convert, and then click Convert to Dynamic Disk. You need to right click the gray area that contains the name of the disk to get the menu.
*
Select the check box that is next to the disk that you want to and then click Ok.
*
Click Convert.
*
Click Yes when you are prompted to convert the disk, and then click Ok.

After you convert a basic disk to a dynamic disk, you cannot convert it back without losing your data. So if you want to go back make sure to back up your files first! You must first delete all dynamic volumes on the disk and then convert the dynamic disk back to a basic disk.
Hope this helps you out.

Please post back if you have any more problems or questions.

Networks

Question